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7319 Need a way to turn off ld "multiple inclusion" warnings
Reviewed by: Martin Bochnig <opensxce@mail.ru>
Reviewed by: Kim Shrier <kshrier@racktopsystems.com>
Reviewed by: Robert Mustacchi <rm@joyent.com>
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1 1 LD(1) User Commands LD(1)
2 2
3 3
4 4
5 5 NAME
6 6 ld - link-editor for object files
7 7
8 8 SYNOPSIS
9 9 ld [-32 | -64] [-a | -r] [-b] [-Bdirect | nodirect]
10 10 [-B dynamic | static] [-B eliminate] [-B group] [-B local]
11 11 [-B reduce] [-B symbolic] [-c name] [-C] [-d y | n]
12 12 [-D token,...] [-e epsym] [-f name | -F name] [-G] [-h name]
13 13 [-i] [-I name] [-l x] [-L path] [-m] [-M mapfile]
14 14 [-N string] [-o outfile] [-p auditlib] [-P auditlib]
15 15 [-Q y | n] [-R path] [-s] [-S supportlib] [-t]
16 16 [-u symname] [-V] [-Y P,dirlist] [-z absexec]
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17 17 [-z allextract | defaultextract | weakextract ] [-z altexec64]
18 18 [-z assert-deflib ] [ -z assert-deflib=libname ]
19 19 [-z combreloc | nocombreloc ] [-z defs | nodefs]
20 20 [-z direct | nodirect] [-z endfiltee]
21 21 [-z fatal-warnings | nofatal-warnings ] [-z finiarray=function]
22 22 [-z globalaudit] [-z groupperm | nogroupperm]
23 23 [-z guidance[=id1,id2...] [-z help ]
24 24 [-z ignore | record] [-z initarray=function] [-z initfirst]
25 25 [-z interpose] [-z lazyload | nolazyload]
26 26 [-z ld32=arg1,arg2,...] [-z ld64=arg1,arg2,...]
27 - [-z loadfltr] [-z muldefs] [-z nocompstrtab] [-z nodefaultlib]
27 + [-z loadfltr] [-z muldefs] [-z mulincl] [-z nocompstrtab] [-z nodefaultlib]
28 28 [-z nodelete] [-z nodlopen] [-z nodump] [-z noldynsym]
29 29 [-z nopartial] [-z noversion] [-z now] [-z origin]
30 30 [-z preinitarray=function] [-z redlocsym] [-z relaxreloc]
31 31 [-z rescan-now] [-z recan] [-z rescan-start ... -z rescan-end]]
32 32 [-z target=sparc|x86] [-z text | textwarn | textoff]
33 33 [-z verbose] [-z wrap=symbol] filename...
34 34
35 35
36 36 DESCRIPTION
37 37 The link-editor, ld, combines relocatable object files by resolving
38 38 symbol references to symbol definitions, together with performing
39 39 relocations. ld operates in two modes, static or dynamic, as governed
40 40 by the -d option. In all cases, the output of ld is left in the file
41 41 a.out by default. See NOTES.
42 42
43 43
44 44 In dynamic mode, -dy, the default, relocatable object files that are
45 45 provided as arguments are combined to produce an executable object
46 46 file. This file is linked at execution with any shared object files
47 47 that are provided as arguments. If the -G option is specified,
48 48 relocatable object files are combined to produce a shared object.
49 49 Without the -G option, a dynamic executable is created.
50 50
51 51
52 52 In static mode, -dn, relocatable object files that are provided as
53 53 arguments are combined to produce a static executable file. If the -r
54 54 option is specified, relocatable object files are combined to produce
55 55 one relocatable object file. See Static Executables.
56 56
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57 57
58 58 Dynamic linking is the most common model for combining relocatable
59 59 objects, and the eventual creation of processes within Solaris. This
60 60 environment tightly couples the work of the link-editor and the runtime
61 61 linker, ld.so.1(1). Both of these utilities, together with their
62 62 related technologies and utilities, are extensively documented in the
63 63 Linker and Libraries Guide.
64 64
65 65
66 66 If any argument is a library, ld by default searches the library
67 - exactly once at the point the library is encountered on the argument
68 - list. The library can be either a shared object or relocatable archive.
69 - See ar.h(3HEAD)).
67 + exactly once at the point the library is first encountered on the
68 + argument list. The library can be either a shared object or relocatable
69 + archive. See ar.h(3HEAD)).
70 70
71 71
72 72 A shared object consists of an indivisible, whole unit that has been
73 73 generated by a previous link-edit of one or more input files. When the
74 74 link-editor processes a shared object, the entire contents of the
75 75 shared object become a logical part of the resulting output file image.
76 76 The shared object is not physically copied during the link-edit as its
77 77 actual inclusion is deferred until process execution. This logical
78 78 inclusion means that all symbol entries defined in the shared object
79 79 are made available to the link-editing process. See Chapter 4, Shared
80 80 Objects, in Linker and Libraries Guide
81 81
82 82
83 83 For an archive library, ld loads only those routines that define an
84 84 unresolved external reference. ld searches the symbol table of the
85 85 archive library sequentially to resolve external references that can be
86 86 satisfied by library members. This search is repeated until no external
87 87 references can be resolved by the archive. Thus, the order of members
88 88 in the library is functionally unimportant, unless multiple library
89 89 members exist that define the same external symbol. Archive libraries
90 90 that have interdependencies can require multiple command line
91 91 definitions, or the use of one of the -z rescan options. See Archive
92 92 Processing in Linker and Libraries Guide.
93 93
94 94
95 95 ld is a cross link-editor, able to link 32-bit objects or 64-bit
96 96 objects, for Sparc or x86 targets. ld uses the ELF class and machine
97 97 type of the first relocatable object on the command line to govern the
98 98 mode in which to operate. The mixing of 32-bit objects and 64-bit
99 99 objects is not permitted. Similarly, only objects of a single machine
100 100 type are allowed. See the -32, -64 and -z target options, and the
101 101 LD_NOEXEC_64 environment variable.
102 102
103 103 Static Executables
104 104 The creation of static executables has been discouraged for many
105 105 releases. In fact, 64-bit system archive libraries have never been
106 106 provided. Because a static executable is built against system archive
107 107 libraries, the executable contains system implementation details. This
108 108 self-containment has a number of drawbacks.
109 109
110 110 o The executable is immune to the benefits of system patches
111 111 delivered as shared objects. The executable therefore, must
112 112 be rebuilt to take advantage of many system improvements.
113 113
114 114 o The ability of the executable to run on future releases can
115 115 be compromised.
116 116
117 117 o The duplication of system implementation details negatively
118 118 affects system performance.
119 119
120 120
121 121 With Solaris 10, 32-bit system archive libraries are no longer
122 122 provided. Without these libraries, specifically libc.a, the creation
123 123 of static executables is no longer achievable without specialized
124 124 system knowledge. However, the capability of ld to process static
125 125 linking options, and the processing of archive libraries, remains
126 126 unchanged.
127 127
128 128 OPTIONS
129 129 The following options are supported.
130 130
131 131 -32 | -64
132 132
133 133 Creates a 32-bit, or 64-bit object.
134 134
135 135 By default, the class of the object being generated is determined
136 136 from the first ELF object processed from the command line. If no
137 137 objects are specified, the class is determined by the first object
138 138 encountered within the first archive processed from the command
139 139 line. If there are no objects or archives, the link-editor creates
140 140 a 32-bit object.
141 141
142 142 The -64 option is required to create a 64-bit object solely from a
143 143 mapfile.
144 144
145 145 This -32 or -64 options can also be used in the rare case of
146 146 linking entirely from an archive that contains a mixture of 32 and
147 147 64-bit objects. If the first object in the archive is not the class
148 148 of the object that is required to be created, then the -32 or -64
149 149 option can be used to direct the link-editor. See The 32-bit link-
150 150 editor and 64-bit link-editor in Linker and Libraries Guide.
151 151
152 152
153 153 -a
154 154
155 155 In static mode only, produces an executable object file. Undefined
156 156 references are not permitted. This option is the default behavior
157 157 for static mode. The -a option can not be used with the -r option.
158 158 See Static Executables under DESCRIPTION.
159 159
160 160
161 161 -b
162 162
163 163 In dynamic mode only, provides no special processing for dynamic
164 164 executable relocations that reference symbols in shared objects.
165 165 Without the -b option, the link-editor applies techniques within a
166 166 dynamic executable so that the text segment can remain read-only.
167 167 One technique is the creation of special position-independent
168 168 relocations for references to functions that are defined in shared
169 169 objects. Another technique arranges for data objects that are
170 170 defined in shared objects to be copied into the memory image of an
171 171 executable at runtime.
172 172
173 173 The -b option is intended for specialized dynamic objects and is
174 174 not recommended for general use. Its use suppresses all specialized
175 175 processing required to ensure an object's shareability, and can
176 176 even prevent the relocation of 64-bit executables.
177 177
178 178
179 179 -B direct | nodirect
180 180
181 181 These options govern direct binding. -B direct establishes direct
182 182 binding information by recording the relationship between each
183 183 symbol reference together with the dependency that provides the
184 184 definition. In addition, direct binding information is established
185 185 between each symbol reference and an associated definition within
186 186 the object being created. The runtime linker uses this information
187 187 to search directly for a symbol in the associated object rather
188 188 than to carry out a default symbol search.
189 189
190 190 Direct binding information can only be established to dependencies
191 191 specified with the link-edit. Thus, you should use the -z defs
192 192 option. Objects that wish to interpose on symbols in a direct
193 193 binding environment should identify themselves as interposers with
194 194 the -z interpose option. The use of -B direct enables -z lazyload
195 195 for all dependencies.
196 196
197 197 The -B nodirect option prevents any direct binding to the
198 198 interfaces offered by the object being created. The object being
199 199 created can continue to directly bind to external interfaces by
200 200 specifying the -z direct option. See Appendix D, Direct Bindings,
201 201 in Linker and Libraries Guide.
202 202
203 203
204 204 -B dynamic | static
205 205
206 206 Options governing library inclusion. -B dynamic is valid in dynamic
207 207 mode only. These options can be specified any number of times on
208 208 the command line as toggles: if the -B static option is given, no
209 209 shared objects are accepted until -B dynamic is seen. See the -l
210 210 option.
211 211
212 212
213 213 -B eliminate
214 214
215 215 Causes any global symbols, not assigned to a version definition, to
216 216 be eliminated from the symbol table. Version definitions can be
217 217 supplied by means of a mapfile to indicate the global symbols that
218 218 should remain visible in the generated object. This option achieves
219 219 the same symbol elimination as the auto-elimination directive that
220 220 is available as part of a mapfile version definition. This option
221 221 can be useful when combining versioned and non-versioned
222 222 relocatable objects. See also the -B local option and the -B reduce
223 223 option. See Defining Additional Symbols with a mapfile in Linker
224 224 and Libraries Guide.
225 225
226 226
227 227 -B group
228 228
229 229 Establishes a shared object and its dependencies as a group.
230 230 Objects within the group are bound to other members of the group at
231 231 runtime. This mode is similar to adding the object to the process
232 232 by using dlopen(3C) with the RTLD_GROUP mode. An object that has an
233 233 explicit dependency on a object identified as a group, becomes a
234 234 member of the group.
235 235
236 236 As the group must be self contained, use of the -B group option
237 237 also asserts the -z defs option.
238 238
239 239
240 240 -B local
241 241
242 242 Causes any global symbols, not assigned to a version definition, to
243 243 be reduced to local. Version definitions can be supplied by means
244 244 of a mapfile to indicate the global symbols that should remain
245 245 visible in the generated object. This option achieves the same
246 246 symbol reduction as the auto-reduction directive that is available
247 247 as part of a mapfile version definition. This option can be useful
248 248 when combining versioned and non-versioned relocatable objects. See
249 249 also the -B eliminate option and the -B reduce option. See Defining
250 250 Additional Symbols with a mapfile in Linker and Libraries Guide.
251 251
252 252
253 253 -B reduce
254 254
255 255 When generating a relocatable object, causes the reduction of
256 256 symbolic information defined by any version definitions. Version
257 257 definitions can be supplied by means of a mapfile to indicate the
258 258 global symbols that should remain visible in the generated object.
259 259 By default, when a relocatable object is generated, version
260 260 definitions are only recorded in the output image. The actual
261 261 reduction of symbolic information is carried out when the object is
262 262 used in the construction of a dynamic executable or shared object.
263 263 The -B reduce option is applied automatically when a dynamic
264 264 executable or shared object is created.
265 265
266 266
267 267 -B symbolic
268 268
269 269 In dynamic mode only. When building a shared object, binds
270 270 references to global symbols to their definitions, if available,
271 271 within the object. Normally, references to global symbols within
272 272 shared objects are not bound until runtime, even if definitions are
273 273 available. This model allows definitions of the same symbol in an
274 274 executable or other shared object to override the object's own
275 275 definition. ld issues warnings for undefined symbols unless -z defs
276 276 overrides.
277 277
278 278 The -B symbolic option is intended for specialized dynamic objects
279 279 and is not recommended for general use. To reduce the runtime
280 280 relocation processing that is required an object, the creation of a
281 281 version definition is recommended.
282 282
283 283
284 284 -c name
285 285
286 286 Records the configuration file name for use at runtime.
287 287 Configuration files can be employed to alter default search paths,
288 288 provide a directory cache, together with providing alternative
289 289 object dependencies. See crle(1).
290 290
291 291
292 292 -C
293 293
294 294 Demangles C++ symbol names displayed in diagnostic messages.
295 295
296 296
297 297 -d y | n
298 298
299 299 When -d y, the default, is specified, ld uses dynamic linking. When
300 300 -d n is specified, ld uses static linking. See Static Executables
301 301 under DESCRIPTION, and -B dynamic|static.
302 302
303 303
304 304 -D token,...
305 305
306 306 Prints debugging information as specified by each token, to the
307 307 standard error. The special token help indicates the full list of
308 308 tokens available. See Debugging Aids in Linker and Libraries Guide.
309 309
310 310
311 311 -e epsym
312 312 --entry epsym
313 313
314 314 Sets the entry point address for the output file to be the symbol
315 315 epsym.
316 316
317 317
318 318 -f name
319 319 --auxiliary name
320 320
321 321 Useful only when building a shared object. Specifies that the
322 322 symbol table of the shared object is used as an auxiliary filter on
323 323 the symbol table of the shared object specified by name. Multiple
324 324 instances of this option are allowed. This option can not be
325 325 combined with the -F option. See Generating Auxiliary Filters in
326 326 Linker and Libraries Guide.
327 327
328 328
329 329 -F name
330 330 --filter name
331 331
332 332 Useful only when building a shared object. Specifies that the
333 333 symbol table of the shared object is used as a filter on the symbol
334 334 table of the shared object specified by name. Multiple instances of
335 335 this option are allowed. This option can not be combined with the
336 336 -f option. See Generating Standard Filters in Linker and Libraries
337 337 Guide.
338 338
339 339
340 340 -G
341 341 -shared
342 342
343 343 In dynamic mode only, produces a shared object. Undefined symbols
344 344 are allowed. See Chapter 4, Shared Objects, in Linker and
345 345 Libraries Guide.
346 346
347 347
348 348 -h name
349 349 --soname name
350 350
351 351 In dynamic mode only, when building a shared object, records name
352 352 in the object's dynamic section. name is recorded in any dynamic
353 353 objects that are linked with this object rather than the object's
354 354 file system name. Accordingly, name is used by the runtime linker
355 355 as the name of the shared object to search for at runtime. See
356 356 Recording a Shared Object Name in Linker and Libraries Guide.
357 357
358 358
359 359 -i
360 360
361 361 Ignores LD_LIBRARY_PATH. This option is useful when an
362 362 LD_LIBRARY_PATH setting is in effect to influence the runtime
363 363 library search, which would interfere with the link-editing being
364 364 performed.
365 365
366 366
367 367 -I name
368 368 --dynamic-linker name
369 369
370 370 When building an executable, uses name as the path name of the
371 371 interpreter to be written into the program header. The default in
372 372 static mode is no interpreter. In dynamic mode, the default is the
373 373 name of the runtime linker, ld.so.1(1). Either case can be
374 374 overridden by -I name. exec(2) loads this interpreter when the
375 375 a.out is loaded, and passes control to the interpreter rather than
376 376 to the a.out directly.
377 377
378 378
379 379 -l x
380 380 --library x
381 381
382 382 Searches a library libx.so or libx.a, the conventional names for
383 383 shared object and archive libraries, respectively. In dynamic
384 384 mode, unless the -B static option is in effect, ld searches each
385 385 directory specified in the library search path for a libx.so or
386 386 libx.a file. The directory search stops at the first directory
387 387 containing either. ld chooses the file ending in .so if -lx expands
388 388 to two files with names of the form libx.so and libx.a. If no
389 389 libx.so is found, then ld accepts libx.a. In static mode, or when
390 390 the -B static option is in effect, ld selects only the file ending
391 391 in .a. ld searches a library when the library is encountered, so
392 392 the placement of -l is significant. See Linking With Additional
393 393 Libraries in Linker and Libraries Guide.
394 394
395 395
396 396 -L path
397 397 --library-path path
398 398
399 399 Adds path to the library search directories. ld searches for
400 400 libraries first in any directories specified by the -L options and
401 401 then in the standard directories. This option is useful only if the
402 402 option precedes the -l options to which the -L option applies. See
403 403 Directories Searched by the Link-Editor in Linker and Libraries
404 404 Guide.
405 405
406 406 The environment variable LD_LIBRARY_PATH can be used to supplement
407 407 the library search path, however the -L option is recommended, as
408 408 the environment variable is also interpreted by the runtime
409 409 environment. See LD_LIBRARY_PATH under ENVIRONMENT VARIABLES.
410 410
411 411
412 412 -m
413 413
414 414 Produces a memory map or listing of the input/output sections,
415 415 together with any non-fatal multiply-defined symbols, on the
416 416 standard output.
417 417
418 418
419 419 -M mapfile
420 420
421 421 Reads mapfile as a text file of directives to ld. This option can
422 422 be specified multiple times. If mapfile is a directory, then all
423 423 regular files, as defined by stat(2), within the directory are
424 424 processed. See Chapter 9, Mapfile Option, in Linker and Libraries
425 425 Guide. Example mapfiles are provided in /usr/lib/ld. See FILES.
426 426
427 427
428 428 -N string
429 429
430 430 This option causes a DT_NEEDED entry to be added to the .dynamic
431 431 section of the object being built. The value of the DT_NEEDED
432 432 string is the string that is specified on the command line. This
433 433 option is position dependent, and the DT_NEEDED .dynamic entry is
434 434 relative to the other dynamic dependencies discovered on the link-
435 435 edit line. This option is useful for specifying dependencies within
436 436 device driver relocatable objects when combined with the -dy and -r
437 437 options.
438 438
439 439
440 440 -o outfile
441 441 --output outfile
442 442
443 443 Produces an output object file that is named outfile. The name of
444 444 the default object file is a.out.
445 445
446 446
447 447 -p auditlib
448 448
449 449 Identifies an audit library, auditlib. This audit library is used
450 450 to audit the object being created at runtime. A shared object
451 451 identified as requiring auditing with the -p option, has this
452 452 requirement inherited by any object that specifies the shared
453 453 object as a dependency. See the -P option. See Runtime Linker
454 454 Auditing Interface in Linker and Libraries Guide.
455 455
456 456
457 457 -P auditlib
458 458
459 459 Identifies an audit library, auditlib. This audit library is used
460 460 to audit the dependencies of the object being created at runtime.
461 461 Dependency auditing can also be inherited from dependencies that
462 462 are identified as requiring auditing. See the -p option, and the -z
463 463 globalaudit option. See Runtime Linker Auditing Interface in Linker
464 464 and Libraries Guide.
465 465
466 466
467 467 -Q y | n
468 468
469 469 Under -Q y, an ident string is added to the .comment section of the
470 470 output file. This string identifies the version of the ld used to
471 471 create the file. This results in multiple ld idents when there have
472 472 been multiple linking steps, such as when using ld -r. This
473 473 identification is identical with the default action of the cc
474 474 command. -Q n suppresses version identification. .comment sections
475 475 can be manipulated by the mcs(1) utility.
476 476
477 477
478 478 -r
479 479 --relocatable
480 480
481 481 Combines relocatable object files to produce one relocatable object
482 482 file. ld does not complain about unresolved references. This
483 483 option cannot be used with the -a option.
484 484
485 485
486 486 -R path
487 487 -rpath path
488 488
489 489 A colon-separated list of directories used to specify library
490 490 search directories to the runtime linker. If present and not NULL,
491 491 the path is recorded in the output object file and passed to the
492 492 runtime linker. Multiple instances of this option are concatenated
493 493 together with each path separated by a colon. See Directories
494 494 Searched by the Runtime Linker in Linker and Libraries Guide.
495 495
496 496 The use of a runpath within an associated object is preferable to
497 497 setting global search paths such as through the LD_LIBRARY_PATH
498 498 environment variable. Only the runpaths that are necessary to find
499 499 the objects dependencies should be recorded. ldd(1) can also be
500 500 used to discover unused runpaths in dynamic objects, when used with
501 501 the -U option.
502 502
503 503 Various tokens can also be supplied with a runpath that provide a
504 504 flexible means of identifying system capabilities or an objects
505 505 location. See Appendix C, Establishing Dependencies with Dynamic
506 506 String Tokens, in Linker and Libraries Guide. The $ORIGIN token is
507 507 especially useful in allowing dynamic objects to be relocated to
508 508 different locations in the file system.
509 509
510 510
511 511 -s
512 512 --strip-all
513 513
514 514 Strips symbolic information from the output file. Any debugging
515 515 information, that is, .line, .debug*, and .stab* sections, and
516 516 their associated relocation entries are removed. Except for
517 517 relocatable files, a symbol table SHT_SYMTAB and its associated
518 518 string table section are not created in the output object file. The
519 519 elimination of a SHT_SYMTAB symbol table can reduce the .stab*
520 520 debugging information that is generated using the compiler drivers
521 521 -g option. See the -z redlocsym and -z noldynsym options.
522 522
523 523
524 524 -S supportlib
525 525
526 526 The shared object supportlib is loaded with ld and given
527 527 information regarding the linking process. Shared objects that are
528 528 defined by using the -S option can also be supplied using the
529 529 SGS_SUPPORT environment variable. See Link-Editor Support Interface
530 530 in Linker and Libraries Guide.
531 531
532 532
533 533 -t
534 534
535 535 Turns off the warning for multiply-defined symbols that have
536 536 different sizes or different alignments.
537 537
538 538
539 539 -u symname
540 540 --undefined symname
541 541
542 542 Enters symname as an undefined symbol in the symbol table. This
543 543 option is useful for loading entirely from an archive library. In
544 544 this instance, an unresolved reference is needed to force the
545 545 loading of the first routine. The placement of this option on the
546 546 command line is significant. This option must be placed before the
547 547 library that defines the symbol. See Defining Additional Symbols
548 548 with the u option in Linker and Libraries Guide.
549 549
550 550
551 551 -V
552 552 --version
553 553
554 554 Outputs a message giving information about the version of ld being
555 555 used.
556 556
557 557
558 558 -Y P,dirlist
559 559
560 560 Changes the default directories used for finding libraries. dirlist
561 561 is a colon-separated path list.
562 562
563 563
564 564 -z absexec
565 565
566 566 Useful only when building a dynamic executable. Specifies that
567 567 references to external absolute symbols should be resolved
568 568 immediately instead of being left for resolution at runtime. In
569 569 very specialized circumstances, this option removes text
570 570 relocations that can result in excessive swap space demands by an
571 571 executable.
572 572
573 573
574 574 -z allextract | defaultextract | weakextract
575 575 --whole-archive | --no-whole-archive
576 576
577 577 Alters the extraction criteria of objects from any archives that
578 578 follow. By default, archive members are extracted to satisfy
579 579 undefined references and to promote tentative definitions with data
580 580 definitions. Weak symbol references do not trigger extraction.
581 581 Under the -z allextract or --whole-archive options, all archive
582 582 members are extracted from the archive. Under -z weakextract, weak
583 583 references trigger archive extraction. The -z defaultextract or
584 584 --no-whole-archive options provide a means of returning to the
585 585 default following use of the former extract options. See Archive
586 586 Processing in Linker and Libraries Guide.
587 587
588 588
589 589 -z altexec64
590 590
591 591 Execute the 64-bit ld. The creation of very large 32-bit objects
592 592 can exhaust the virtual memory that is available to the 32-bit ld.
593 593 The -z altexec64 option can be used to force the use of the
594 594 associated 64-bit ld. The 64-bit ld provides a larger virtual
595 595 address space for building 32-bit objects. See The 32-bit link-
596 596 editor and 64-bit link-editor in Linker and Libraries Guide.
597 597
598 598
599 599 -z combreloc | nocombreloc
600 600
601 601 By default, ld combines multiple relocation sections when building
602 602 executables or shared objects. This section combination differs
603 603 from relocatable objects, in which relocation sections are
604 604 maintained in a one-to-one relationship with the sections to which
605 605 the relocations must be applied. The -z nocombreloc option disables
606 606 this merging of relocation sections, and preserves the one-to-one
607 607 relationship found in the original relocatable objects.
608 608
609 609 ld sorts the entries of data relocation sections by their symbol
610 610 reference. This sorting reduces runtime symbol lookup. When
611 611 multiple relocation sections are combined, this sorting produces
612 612 the least possible relocation overhead when objects are loaded into
613 613 memory, and speeds the runtime loading of dynamic objects.
614 614
615 615 Historically, the individual relocation sections were carried over
616 616 to any executable or shared object, and the -z combreloc option was
617 617 required to enable the relocation section merging previously
618 618 described. Relocation section merging is now the default. The -z
619 619 combreloc option is still accepted for the benefit of old build
620 620 environments, but the option is unnecessary, and has no effect.
621 621
622 622
623 623 -z assert-deflib
624 624 -z assert-deflib=libname
625 625
626 626 Enables warnings that check the location of where libraries passed
627 627 in with -l are found. If the link-editor finds a library on its
628 628 default search path it will emit a warning. This warning can be
629 629 made fatal in conjunction with the option -z fatal-warnings.
630 630 Passing libname white lists a library from this check. The library
631 631 must be the full name of the library, e.g. libc.so. To white list
632 632 multiple libraries, the -z assert-deflib=libname option can be
633 633 repeated multiple times. This option is useful when trying to build
634 634 self-contained objects where a referenced library might exist in
635 635 the default system library path and in alternate paths specified by
636 636 -L, but you only want the alternate paths to be used.
637 637
638 638
639 639 -z defs | nodefs
640 640 --no-undefined
641 641
642 642 The -z defs option and the --no-undefined option force a fatal
643 643 error if any undefined symbols remain at the end of the link. This
644 644 mode is the default when an executable is built. For historic
645 645 reasons, this mode is not the default when building a shared
646 646 object. Use of the -z defs option is recommended, as this mode
647 647 assures the object being built is self-contained. A self-contained
648 648 object has all symbolic references resolved internally, or to the
649 649 object's immediate dependencies.
650 650
651 651 The -z nodefs option allows undefined symbols. For historic
652 652 reasons, this mode is the default when a shared object is built.
653 653 When used with executables, the behavior of references to such
654 654 undefined symbols is unspecified. Use of the -z nodefs option is
655 655 not recommended.
656 656
657 657
658 658 -z direct | nodirect
659 659
660 660 Enables or disables direct binding to any dependencies that follow
661 661 on the command line. These options allow finer control over direct
662 662 binding than the global counterpart -B direct. The -z direct option
663 663 also differs from the -B direct option in the following areas.
664 664 Direct binding information is not established between a symbol
665 665 reference and an associated definition within the object being
666 666 created. Lazy loading is not enabled.
667 667
668 668
669 669 -z endfiltee
670 670
671 671 Marks a filtee so that when processed by a filter, the filtee
672 672 terminates any further filtee searches by the filter. See Reducing
673 673 Filtee Searches in Linker and Libraries Guide.
674 674
675 675
676 676 -z fatal-warnings | nofatal-warnings
677 677 --fatal-warnings | --no-fatal-warnings
678 678
679 679 Controls the behavior of warnings emitted from the link-editor.
680 680 Setting -z fatal-warnings promotes warnings emitted by the link-
681 681 editor to fatal errors that will cause the link-editor to fail
682 682 before linking. -z nofatal-warnings instead demotes these warnings
683 683 such that they will not cause the link-editor to exit prematurely.
684 684
685 685
686 686
687 687 -z finiarray=function
688 688
689 689 Appends an entry to the .finiarray section of the object being
690 690 built. If no .finiarray section is present, a section is created.
691 691 The new entry is initialized to point to function. See
692 692 Initialization and Termination Sections in Linker and Libraries
693 693 Guide.
694 694
695 695
696 696 -z globalaudit
697 697
698 698 This option supplements an audit library definition that has been
699 699 recorded with the -P option. This option is only meaningful when
700 700 building a dynamic executable. Audit libraries that are defined
701 701 within an object with the -P option typically allow for the
702 702 auditing of the immediate dependencies of the object. The -z
703 703 globalaudit promotes the auditor to a global auditor, thus allowing
704 704 the auditing of all dependencies. See Invoking the Auditing
705 705 Interface in Linker and Libraries Guide.
706 706
707 707 An auditor established with the -P option and the -z globalaudit
708 708 option, is equivalent to the auditor being established with the
709 709 LD_AUDIT environment variable. See ld.so.1(1).
710 710
711 711
712 712 -z groupperm | nogroupperm
713 713
714 714 Assigns, or deassigns each dependency that follows to a unique
715 715 group. The assignment of a dependency to a group has the same
716 716 effect as if the dependency had been built using the -B group
717 717 option.
718 718
719 719
720 720 -z guidance[=id1,id2...]
721 721
722 722 Give messages suggesting link-editor features that could improve
723 723 the resulting dynamic object.
724 724
725 725 Specific classes of suggestion can be silenced by specifying an
726 726 optional comma separated list of guidance identifiers.
727 727
728 728 The current classes of suggestion provided are:
729 729
730 730
731 731 Enable use of direct binding
732 732
733 733 Suggests that -z direct or -B direct be present prior to any
734 734 specified dependency. This allows predictable symbol binding
735 735 at runtime.
736 736
737 737 Can be disabled with -z guidance=nodirect
738 738
739 739
740 740 Enable lazy dependency loading
741 741
742 742 Suggests that -z lazyload be present prior to any specified
743 743 dependency. This allows the dynamic object to be loaded more
744 744 quickly.
745 745
746 746 Can be disabled with -z guidance=nolazyload.
747 747
748 748
749 749 Shared objects should define all their dependencies.
750 750
751 751 Suggests that -z defs be specified on the link-editor command
752 752 line. Shared objects that explicitly state all their
753 753 dependencies behave more predictably when used.
754 754
755 755 Can be be disabled with -z guidance=nodefs
756 756
757 757
758 758 Version 2 mapfile syntax
759 759
760 760 Suggests that any specified mapfiles use the more readable
761 761 version 2 syntax.
762 762
763 763 Can be disabled with -z guidance=nomapfile.
764 764
765 765
766 766 Read-only text segment
767 767
768 768 Should any runtime relocations within the text segment exist,
769 769 suggests that the object be compiled with position independent
770 770 code (PIC). Keeping large allocatable sections read-only
771 771 allows them to be shared between processes using a given shared
772 772 object.
773 773
774 774 Can be disabled with -z guidance=notext
775 775
776 776
777 777 No unused dependencies
778 778
779 779 Suggests that any dependency not referenced by the resulting
780 780 dynamic object be removed from the link-editor command line.
781 781
782 782 Can be disabled with -z guidance=nounused.
783 783
784 784
785 785 -z help
786 786 --help
787 787
788 788 Print a summary of the command line options on the standard output
789 789 and exit.
790 790
791 791
792 792 -z ignore | record
793 793
794 794 Ignores, or records, dynamic dependencies that are not referenced
795 795 as part of the link-edit. Ignores, or records, unreferenced ELF
796 796 sections from the relocatable objects that are read as part of the
797 797 link-edit. By default, -z record is in effect.
798 798
799 799 If an ELF section is ignored, the section is eliminated from the
800 800 output file being generated. A section is ignored when three
801 801 conditions are true. The eliminated section must contribute to an
802 802 allocatable segment. The eliminated section must provide no global
803 803 symbols. No other section from any object that contributes to the
804 804 link-edit, must reference an eliminated section.
805 805
806 806
807 807 -z initarray=function
808 808
809 809 Appends an entry to the .initarray section of the object being
810 810 built. If no .initarray section is present, a section is created.
811 811 The new entry is initialized to point to function. See
812 812 Initialization and Termination Sections in Linker and Libraries
813 813 Guide.
814 814
815 815
816 816 -z initfirst
817 817
818 818 Marks the object so that its runtime initialization occurs before
819 819 the runtime initialization of any other objects brought into the
820 820 process at the same time. In addition, the object runtime
821 821 finalization occurs after the runtime finalization of any other
822 822 objects removed from the process at the same time. This option is
823 823 only meaningful when building a shared object.
824 824
825 825
826 826 -z interpose
827 827
828 828 Marks the object as an interposer. At runtime, an object is
829 829 identified as an explicit interposer if the object has been tagged
830 830 using the -z interpose option. An explicit interposer is also
831 831 established when an object is loaded using the LD_PRELOAD
832 832 environment variable. Implicit interposition can occur because of
833 833 the load order of objects, however, this implicit interposition is
834 834 unknown to the runtime linker. Explicit interposition can ensure
835 835 that interposition takes place regardless of the order in which
836 836 objects are loaded. Explicit interposition also ensures that the
837 837 runtime linker searches for symbols in any explicit interposers
838 838 when direct bindings are in effect.
839 839
840 840
841 841 -z lazyload | nolazyload
842 842
843 843 Enables or disables the marking of dynamic dependencies to be
844 844 lazily loaded. Dynamic dependencies which are marked lazyload are
845 845 not loaded at initial process start-up. These dependencies are
846 846 delayed until the first binding to the object is made. Note: Lazy
847 847 loading requires the correct declaration of dependencies, together
848 848 with associated runpaths for each dynamic object used within a
849 849 process. See Lazy Loading of Dynamic Dependencies in Linker and
850 850 Libraries Guide.
851 851
852 852
853 853 -z ld32=arg1,arg2,...
854 854 -z ld64=arg1,arg2,...
855 855
856 856 The class of the link-editor is affected by the class of the output
857 857 file being created and by the capabilities of the underlying
858 858 operating system. The -z ld[32|64] options provide a means of
859 859 defining any link-editor argument. The defined argument is only
860 860 interpreted, respectively, by the 32-bit class or 64-bit class of
861 861 the link-editor.
862 862
863 863 For example, support libraries are class specific, so the correct
864 864 class of support library can be ensured using:
865 865
866 866 ld ... -z ld32=-Saudit32.so.1 -z ld64=-Saudit64.so.1 ...
867 867
868 868
869 869 The class of link-editor that is invoked is determined from the ELF
870 870 class of the first relocatable file that is seen on the command
871 871 line. This determination is carried out prior to any -z ld[32|64]
872 872 processing.
873 873
874 874
875 875 -z loadfltr
876 876
877 877 Marks a filter to indicate that filtees must be processed
878 878 immediately at runtime. Normally, filter processing is delayed
879 879 until a symbol reference is bound to the filter. The runtime
880 880 processing of an object that contains this flag mimics that which
881 881 occurs if the LD_LOADFLTR environment variable is in effect. See
882 882 the ld.so.1(1).
883 883
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884 884
885 885 -z muldefs
886 886 --allow-multiple-definition
887 887
888 888 Allows multiple symbol definitions. By default, multiple symbol
889 889 definitions that occur between relocatable objects result in a
890 890 fatal error condition. This option, suppresses the error condition,
891 891 allowing the first symbol definition to be taken.
892 892
893 893
894 + -z mulincl
895 +
896 + Allows multiple inclusion of the same file. By default, a warning
897 + is generated for libraries that are passed multiple times on the
898 + command line. This option suppresses that warning, allowing -z
899 + fatal-warnings to be used when compiling code that makes multiple
900 + inclusions. Note: When a file is specified more than once, only
901 + the first instance is included.
902 +
903 +
894 904 -z nocompstrtab
895 905
896 906 Disables the compression of ELF string tables. By default, string
897 907 compression is applied to SHT_STRTAB sections, and to SHT_PROGBITS
898 908 sections that have their SHF_MERGE and SHF_STRINGS section flags
899 909 set.
900 910
901 911
902 912 -z nodefaultlib
903 913
904 914 Marks the object so that the runtime default library search path,
905 915 used after any LD_LIBRARY_PATH or runpaths, is ignored. This option
906 916 implies that all dependencies of the object can be satisfied from
907 917 its runpath.
908 918
909 919
910 920 -z nodelete
911 921
912 922 Marks the object as non-deletable at runtime. This mode is similar
913 923 to adding the object to the process by using dlopen(3C) with the
914 924 RTLD_NODELETE mode.
915 925
916 926
917 927 -z nodlopen
918 928
919 929 Marks the object as not available to dlopen(3C), either as the
920 930 object specified by the dlopen(), or as any form of dependency
921 931 required by the object specified by the dlopen(). This option is
922 932 only meaningful when building a shared object.
923 933
924 934
925 935 -z nodump
926 936
927 937 Marks the object as not available to dldump(3C).
928 938
929 939
930 940 -z noldynsym
931 941
932 942 Prevents the inclusion of a .SUNW_ldynsym section in dynamic
933 943 executables or sharable libraries. The .SUNW_ldynsym section
934 944 augments the .dynsym section by providing symbols for local
935 945 functions. Local function symbols allow debuggers to display local
936 946 function names in stack traces from stripped programs. Similarly,
937 947 dladdr(3C) is able to supply more accurate results.
938 948
939 949 The -z noldynsym option also prevents the inclusion of the two
940 950 symbol sort sections that are related to the .SUNW_ldynsym section.
941 951 The .SUNW_dynsymsort section provides sorted access to regular
942 952 function and variable symbols. The .SUNW_dyntlssort section
943 953 provides sorted access to thread local storage (TLS) variable
944 954 symbols.
945 955
946 956 The .SUNW_ldynsym, .SUNW_dynsymsort, and .SUNW_dyntlssort sections,
947 957 which becomes part of the allocable text segment of the resulting
948 958 file, cannot be removed by strip(1). Therefore, the -z noldynsym
949 959 option is the only way to prevent their inclusion. See the -s and
950 960 -z redlocsym options.
951 961
952 962
953 963 -z nopartial
954 964
955 965 Partially initialized symbols, that are defined within relocatable
956 966 object files, are expanded in the output file being generated.
957 967
958 968
959 969 -z noversion
960 970
961 971 Does not record any versioning sections. Any version sections or
962 972 associated .dynamic section entries are not generated in the output
963 973 image.
964 974
965 975
966 976 -z now
967 977
968 978 Marks the object as requiring non-lazy runtime binding. This mode
969 979 is similar to adding the object to the process by using dlopen(3C)
970 980 with the RTLD_NOW mode. This mode is also similar to having the
971 981 LD_BIND_NOW environment variable in effect. See ld.so.1(1).
972 982
973 983
974 984 -z origin
975 985
976 986 Marks the object as requiring immediate $ORIGIN processing at
977 987 runtime. This option is only maintained for historic
978 988 compatibility, as the runtime analysis of objects to provide for
979 989 $ORIGIN processing is now default.
980 990
981 991
982 992 -z preinitarray=function
983 993
984 994 Appends an entry to the .preinitarray section of the object being
985 995 built. If no .preinitarray section is present, a section is
986 996 created. The new entry is initialized to point to function. See
987 997 Initialization and Termination Sections in Linker and Libraries
988 998 Guide.
989 999
990 1000
991 1001 -z redlocsym
992 1002
993 1003 Eliminates all local symbols except for the SECT symbols from the
994 1004 symbol table SHT_SYMTAB. All relocations that refer to local
995 1005 symbols are updated to refer to the corresponding SECT symbol. This
996 1006 option allows specialized objects to greatly reduce their symbol
997 1007 table sizes. Eliminated local symbols can reduce the .stab*
998 1008 debugging information that is generated using the compiler drivers
999 1009 -g option. See the -s and -z noldynsym options.
1000 1010
1001 1011
1002 1012 -z relaxreloc
1003 1013
1004 1014 ld normally issues a fatal error upon encountering a relocation
1005 1015 using a symbol that references an eliminated COMDAT section. If -z
1006 1016 relaxreloc is enabled, ld instead redirects such relocations to the
1007 1017 equivalent symbol in the COMDAT section that was kept. -z
1008 1018 relaxreloc is a specialized option, mainly of interest to compiler
1009 1019 authors, and is not intended for general use.
1010 1020
1011 1021
1012 1022 -z rescan-now
1013 1023 -z rescan
1014 1024
1015 1025 These options rescan the archive files that are provided to the
1016 1026 link-edit. By default, archives are processed once as the archives
1017 1027 appear on the command line. Archives are traditionally specified at
1018 1028 the end of the command line so that their symbol definitions
1019 1029 resolve any preceding references. However, specifying archives
1020 1030 multiple times to satisfy their own interdependencies can be
1021 1031 necessary.
1022 1032
1023 1033 -z rescan-now is a positional option, and is processed by the link-
1024 1034 editor immediately when encountered on the command line. All
1025 1035 archives seen on the command line up to that point are immediately
1026 1036 reprocessed in an attempt to locate additional archive members that
1027 1037 resolve symbol references. This archive rescanning is repeated
1028 1038 until a pass over the archives occurs in which no new members are
1029 1039 extracted.
1030 1040
1031 1041 -z rescan is a position independent option. The link-editor defers
1032 1042 the rescan operation until after it has processed the entire
1033 1043 command line, and then initiates a final rescan operation over all
1034 1044 archives seen on the command line. The -z rescan operation can
1035 1045 interact incorrectly with objects that contain
1036 1046 initialization (.init) or finalization (.fini) sections, preventing
1037 1047 the code in those sections from running. For this reason, -z rescan
1038 1048 is deprecated, and use of -z rescan-now is advised.
1039 1049
1040 1050
1041 1051 -z rescan-start ... -z rescan-end
1042 1052 --start-group ... --end-group
1043 1053 -( ... -)
1044 1054
1045 1055 Defines an archive rescan group. This is a positional construct,
1046 1056 and is processed by the link-editor immediately upon encountering
1047 1057 the closing delimiter option. Archives found within the group
1048 1058 delimiter options are reprocessed as a group in an attempt to
1049 1059 locate additional archive members that resolve symbol references.
1050 1060 This archive rescanning is repeated until a pass over the
1051 1061 archives On the occurs in which no new members are extracted.
1052 1062 Archive rescan groups cannot be nested.
1053 1063
1054 1064
1055 1065 -z target=sparc|x86
1056 1066
1057 1067 Specifies the machine type for the output object. Supported targets
1058 1068 are Sparc and x86. The 32-bit machine type for the specified target
1059 1069 is used unless the -64 option is also present, in which case the
1060 1070 corresponding 64-bit machine type is used. By default, the machine
1061 1071 type of the object being generated is determined from the first ELF
1062 1072 object processed from the command line. If no objects are
1063 1073 specified, the machine type is determined by the first object
1064 1074 encountered within the first archive processed from the command
1065 1075 line. If there are no objects or archives, the link-editor assumes
1066 1076 the native machine. This option is useful when creating an object
1067 1077 directly with ld whose input is solely from a mapfile. See the -M
1068 1078 option. It can also be useful in the rare case of linking entirely
1069 1079 from an archive that contains objects of different machine types
1070 1080 for which the first object is not of the desired machine type. See
1071 1081 The 32-bit link-editor and 64-bit link-editor in Linker and
1072 1082 Libraries Guide.
1073 1083
1074 1084
1075 1085 -z text
1076 1086
1077 1087 In dynamic mode only, forces a fatal error if any relocations
1078 1088 against non-writable, allocatable sections remain. For historic
1079 1089 reasons, this mode is not the default when building an executable
1080 1090 or shared object. However, its use is recommended to ensure that
1081 1091 the text segment of the dynamic object being built is shareable
1082 1092 between multiple running processes. A shared text segment incurs
1083 1093 the least relocation overhead when loaded into memory. See
1084 1094 Position-Independent Code in Linker and Libraries Guide.
1085 1095
1086 1096
1087 1097 -z textoff
1088 1098
1089 1099 In dynamic mode only, allows relocations against all allocatable
1090 1100 sections, including non-writable ones. This mode is the default
1091 1101 when building a shared object.
1092 1102
1093 1103
1094 1104 -z textwarn
1095 1105
1096 1106 In dynamic mode only, lists a warning if any relocations against
1097 1107 non-writable, allocatable sections remain. This mode is the default
1098 1108 when building an executable.
1099 1109
1100 1110
1101 1111 -z verbose
1102 1112
1103 1113 This option provides additional warning diagnostics during a link-
1104 1114 edit. Presently, this option conveys suspicious use of
1105 1115 displacement relocations. This option also conveys the restricted
1106 1116 use of static TLS relocations when building shared objects. In
1107 1117 future, this option might be enhanced to provide additional
1108 1118 diagnostics that are deemed too noisy to be generated by default.
1109 1119
1110 1120
1111 1121 -zwrap=symbol
1112 1122 -wrap= symbol
1113 1123 --wrap= symbol
1114 1124
1115 1125 Rename undefined references to symbol in order to allow wrapper
1116 1126 code to be linked into the output object without having to modify
1117 1127 source code. When -z wrap is specified, all undefined references to
1118 1128 symbol are modified to reference __wrap_symbol, and all references
1119 1129 to __real_symbol are modified to reference symbol. The user is
1120 1130 expected to provide an object containing the __wrap_symbol
1121 1131 function. This wrapper function can call __real_symbol in order to
1122 1132 reference the actual function being wrapped.
1123 1133
1124 1134 The following is an example of a wrapper for the malloc(3C)
1125 1135 function:
1126 1136
1127 1137 void *
1128 1138 __wrap_malloc(size_t c)
1129 1139 {
1130 1140 (void) printf("malloc called with %zu\n", c);
1131 1141 return (__real_malloc(c));
1132 1142 }
1133 1143
1134 1144 If you link other code with this file using -z wrap=malloc to
1135 1145 compile all the objects, then all calls to malloc will call the
1136 1146 function __wrap_malloc instead. The call to __real_malloc will call
1137 1147 the real malloc function.
1138 1148
1139 1149 The real and wrapped functions should be maintained in separate
1140 1150 source files. Otherwise, the compiler or assembler may resolve the
1141 1151 call instead of leaving that operation for the link-editor to carry
1142 1152 out, and prevent the wrap from occurring.
1143 1153
1144 1154
1145 1155 ENVIRONMENT VARIABLES
1146 1156 LD_ALTEXEC
1147 1157
1148 1158 An alternative link-editor path name. ld executes, and passes
1149 1159 control to this alternative link-editor. This environment variable
1150 1160 provides a generic means of overriding the default link-editor that
1151 1161 is called from the various compiler drivers. See the -z altexec64
1152 1162 option.
1153 1163
1154 1164
1155 1165 LD_LIBRARY_PATH
1156 1166
1157 1167 A list of directories in which to search for the libraries
1158 1168 specified using the -l option. Multiple directories are separated
1159 1169 by a colon. In the most general case, this environment variable
1160 1170 contains two directory lists separated by a semicolon:
1161 1171
1162 1172 dirlist1;dirlist2
1163 1173
1164 1174
1165 1175 If ld is called with any number of occurrences of -L, as in:
1166 1176
1167 1177 ld ... -Lpath1 ... -Lpathn ...
1168 1178
1169 1179
1170 1180 then the search path ordering is:
1171 1181
1172 1182 dirlist1 path1 ... pathn dirlist2 LIBPATH
1173 1183
1174 1184
1175 1185 When the list of directories does not contain a semicolon, the list
1176 1186 is interpreted as dirlist2.
1177 1187
1178 1188 The LD_LIBRARY_PATH environment variable also affects the runtime
1179 1189 linkers search for dynamic dependencies.
1180 1190
1181 1191 This environment variable can be specified with a _32 or _64
1182 1192 suffix. This makes the environment variable specific, respectively,
1183 1193 to 32-bit or 64-bit processes and overrides any non-suffixed
1184 1194 version of the environment variable that is in effect.
1185 1195
1186 1196
1187 1197 LD_NOEXEC_64
1188 1198
1189 1199 Suppresses the automatic execution of the 64-bit link-editor. By
1190 1200 default, the link-editor executes the 64-bit version when the ELF
1191 1201 class of the first relocatable file identifies a 64-bit object. The
1192 1202 64-bit image that a 32-bit link-editor can create, has some
1193 1203 limitations. However, some link-edits might find the use of the
1194 1204 32-bit link-editor faster.
1195 1205
1196 1206
1197 1207 LD_OPTIONS
1198 1208
1199 1209 A default set of options to ld. LD_OPTIONS is interpreted by ld
1200 1210 just as though its value had been placed on the command line,
1201 1211 immediately following the name used to invoke ld, as in:
1202 1212
1203 1213 ld $LD_OPTIONS ... other-arguments ...
1204 1214
1205 1215
1206 1216
1207 1217
1208 1218 LD_RUN_PATH
1209 1219
1210 1220 An alternative mechanism for specifying a runpath to the link-
1211 1221 editor. See the -R option. If both LD_RUN_PATH and the -R option
1212 1222 are specified, -R supersedes.
1213 1223
1214 1224
1215 1225 SGS_SUPPORT
1216 1226
1217 1227 Provides a colon-separated list of shared objects that are loaded
1218 1228 with the link-editor and given information regarding the linking
1219 1229 process. This environment variable can be specified with a _32 or
1220 1230 _64 suffix. This makes the environment variable specific,
1221 1231 respectively, to the 32-bit or 64-bit class of ld and overrides any
1222 1232 non-suffixed version of the environment variable that is in effect.
1223 1233 See the -S option.
1224 1234
1225 1235
1226 1236
1227 1237 Notice that environment variable-names that begin with the characters
1228 1238 'LD_' are reserved for possible future enhancements to ld and
1229 1239 ld.so.1(1).
1230 1240
1231 1241 FILES
1232 1242 libx.so
1233 1243 shared object libraries.
1234 1244
1235 1245
1236 1246 libx.a
1237 1247 archive libraries.
1238 1248
1239 1249
1240 1250 a.out
1241 1251 default output file.
1242 1252
1243 1253
1244 1254 LIBPATH
1245 1255 For 32-bit libraries, the default search path is
1246 1256 /usr/ccs/lib, followed by /lib, and finally /usr/lib.
1247 1257 For 64-bit libraries, the default search path is
1248 1258 /lib/64, followed by /usr/lib/64.
1249 1259
1250 1260
1251 1261 /usr/lib/ld
1252 1262 A directory containing several mapfiles that can be used
1253 1263 during link-editing. These mapfiles provide various
1254 1264 capabilities, such as defining memory layouts, aligning
1255 1265 bss, and defining non-executable stacks.
1256 1266
1257 1267
1258 1268 ATTRIBUTES
1259 1269 See attributes(5) for descriptions of the following attributes:
1260 1270
1261 1271
1262 1272
1263 1273
1264 1274 +--------------------+-----------------+
1265 1275 | ATTRIBUTE TYPE | ATTRIBUTE VALUE |
1266 1276 +--------------------+-----------------+
1267 1277 |Interface Stability | Committed |
1268 1278 +--------------------+-----------------+
1269 1279
1270 1280 SEE ALSO
1271 1281 as(1), crle(1), gprof(1), ld.so.1(1), ldd(1), mcs(1), pvs(1), exec(2),
1272 1282 stat(2), dlopen(3C), dldump(3C), elf(3ELF), ar.h(3HEAD), a.out(4),
1273 1283 attributes(5)
1274 1284
1275 1285
1276 1286 Linker and Libraries Guide
1277 1287
1278 1288 NOTES
1279 1289 Default options applied by ld are maintained for historic reasons. In
1280 1290 today's programming environment, where dynamic objects dominate,
1281 1291 alternative defaults would often make more sense. However, historic
1282 1292 defaults must be maintained to ensure compatibility with existing
1283 1293 program development environments. Historic defaults are called out
1284 1294 wherever possible in this manual. For a description of the current
1285 1295 recommended options, see Appendix A, Link-Editor Quick Reference, in
1286 1296 Linker and Libraries Guide.
1287 1297
1288 1298
1289 1299 If the file being created by ld already exists, the file is unlinked
1290 1300 after all input files have been processed. A new file with the
1291 1301 specified name is then created. This allows ld to create a new version
1292 1302 of the file, while simultaneously allowing existing processes that are
1293 1303 accessing the old file contents to continue running. If the old file
1294 1304 has no other links, the disk space of the removed file is freed when
1295 1305 the last process referencing the file terminates.
1296 1306
1297 1307
1298 1308 The behavior of ld when the file being created already exists was
1299 1309 changed with SXCE build 43. In older versions, the existing file was
1300 1310 rewritten in place, an approach with the potential to corrupt any
1301 1311 running processes that is using the file. This change has an
1302 1312 implication for output files that have multiple hard links in the file
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1303 1313 system. Previously, all links would remain intact, with all links
1304 1314 accessing the new file contents. The new ld behavior breaks such links,
1305 1315 with the result that only the specified output file name references the
1306 1316 new file. All the other links continue to reference the old file. To
1307 1317 ensure consistent behavior, applications that rely on multiple hard
1308 1318 links to linker output files should explicitly remove and relink the
1309 1319 other file names.
1310 1320
1311 1321
1312 1322
1313 - September 10, 2013 LD(1)
1323 + August 24, 2016 LD(1)
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