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If applicable, add the following below this CDDL HEADER, with the fields enclosed by brackets "[]" replaced with your own identifying information: Portions Copyright [yyyy] [name of copyright owner] 13 .TH UNLINK 2 "Dec 15, 2016" 14 .SH NAME 15 unlink, unlinkat \- remove directory entry 16 .SH SYNOPSIS 17 .LP 18 .nf 19 #include <unistd.h> 20 21 \fBint\fR \fBunlink\fR(\fBconst char *\fR\fIpath\fR); 22 .fi 23 24 .LP 25 .nf 26 \fBint\fR \fBunlinkat\fR(\fBint\fR \fIdirfd\fR, \fBconst char *\fR\fIpath\fR, \fBint\fR \fIflag\fR); 27 .fi 28 29 .SH DESCRIPTION 30 .sp 31 .LP 32 The \fBunlink()\fR function removes a link to a file. If \fIpath\fR names a 33 symbolic link, \fBunlink()\fR removes the symbolic link named by \fIpath\fR and 34 does not affect any file or directory named by the contents of the symbolic 35 link. Otherwise, \fBunlink()\fR removes the link named by the pathname pointed 36 to by \fIpath\fR and decrements the link count of the file referenced by the 37 link. 38 .sp 39 .LP 40 The \fBunlinkat()\fR function also removes a link to a file. See 41 \fBfsattr\fR(5). If the \fIflag\fR argument is 0, the behavior of 42 \fBunlinkat()\fR is the same as \fBunlink()\fR except in the processing of its 43 \fIpath\fR argument. If \fIpath\fR is absolute, \fBunlinkat()\fR behaves the 44 same as \fBunlink()\fR and the \fIdirfd\fR argument is unused. If \fIpath\fR is 45 relative and \fIdirfd\fR has the value \fBAT_FDCWD\fR, defined in 46 <\fBfcntl.h\fR>, \fBunlinkat()\fR also behaves the same as \fBunlink()\fR. 47 Otherwise, \fIpath\fR is resolved relative to the directory referenced by the 48 \fIdirfd\fR argument. 49 .sp 50 .LP 51 If the \fIflag\fR argument is set to the value \fBAT_REMOVEDIR\fR, defined in 52 <\fBfcntl.h\fR>, \fBunlinkat()\fR behaves the same as \fBrmdir\fR(2) except in 53 the processing of the \fIpath\fR argument as described above. 54 .sp 55 .LP 56 When the file's link count becomes 0 and no process has the file open, the 57 space occupied by the file will be freed and the file is no longer accessible. 58 If one or more processes have the file open when the last link is removed, the 59 link is removed before \fBunlink()\fR or \fBunlinkat()\fR returns, but the 60 removal of the file contents is postponed until all references to the file are 61 closed. 62 .sp 63 .LP 64 If the \fIpath\fR argument is a directory and the filesystem supports 65 \fBunlink()\fR and \fBunlinkat()\fR on directories the behaviour is dependent 66 on the filesystem. 67 .sp 68 .LP 69 If the \fIpath\fR argument is a directory and the filesystem does not support 70 \fBunlink()\fR and \fBunlink()\fR on directories (for example, ZFS), the call 71 will fail with \fBerrno\fR set to \fBEPERM\fR. 72 .sp 73 .LP 74 Upon successful completion, \fBunlink()\fR and \fBunlinkat()\fR will mark for 75 update the \fBst_ctime\fR and \fBst_mtime\fR fields of the parent directory. 76 If the file's link count is not 0, the \fBst_ctime\fR field of the file will be 77 marked for update. 78 .SH RETURN VALUES 79 .sp 80 .LP 81 Upon successful completion, \fB0\fR is returned. Otherwise, \fB\(mi1\fR is 82 returned, \fBerrno\fR is set to indicate the error, and the file is not 83 unlinked. 84 .SH ERRORS 85 .sp 86 .LP 87 The \fBunlink()\fR and \fBunlinkat()\fR functions will fail if: 88 .sp 89 .ne 2 90 .na 91 \fB\fBEACCES\fR\fR 92 .ad 93 .RS 16n 94 Search permission is denied for a component of the \fIpath\fR prefix, or write 95 permission is denied on the directory containing the link to be removed. 96 .RE 97 98 .sp 99 .ne 2 100 .na 101 \fB\fBEACCES\fR\fR 102 .ad 103 .RS 16n 104 The parent directory has the sticky bit set and the file is not writable by the 105 user, the user does not own the parent directory, the user does not own the 106 file, and the user is not a privileged user. 107 .RE 108 109 .sp 110 .ne 2 111 .na 112 \fB\fBEBUSY\fR\fR 113 .ad 114 .RS 16n 115 The entry to be unlinked is the mount point for a mounted file system. 116 .RE 117 118 .sp 119 .ne 2 120 .na 121 \fB\fBEFAULT\fR\fR 122 .ad 123 .RS 16n 124 The \fIpath\fR argument points to an illegal address. 125 .RE 126 127 .sp 128 .ne 2 129 .na 130 \fB\fBEILSEQ\fR\fR 131 .ad 132 .RS 16n 133 The path argument includes non-UTF8 characters and the file system accepts only 134 file names where all characters are part of the UTF-8 character codeset. 135 .RE 136 137 .sp 138 .ne 2 139 .na 140 \fB\fBEINTR\fR\fR 141 .ad 142 .RS 16n 143 A signal was caught during the execution of the \fBunlink()\fR function. 144 .RE 145 146 .sp 147 .ne 2 148 .na 149 \fB\fBELOOP\fR\fR 150 .ad 151 .RS 16n 152 Too many symbolic links were encountered in translating \fIpath\fR. 153 .RE 154 155 .sp 156 .ne 2 157 .na 158 \fB\fBENAMETOOLONG\fR\fR 159 .ad 160 .RS 16n 161 The length of the \fIpath\fR argument exceeds \fBPATH_MAX\fR, or the length of 162 a \fIpath\fR component exceeds \fBNAME_MAX\fR while \fB_POSIX_NO_TRUNC\fR is in 163 effect. 164 .RE 165 166 .sp 167 .ne 2 168 .na 169 \fB\fBENOENT\fR\fR 170 .ad 171 .RS 16n 172 The named file does not exist or is a null pathname. 173 .RE 174 175 .sp 176 .ne 2 177 .na 178 \fB\fBENOLINK\fR\fR 179 .ad 180 .RS 16n 181 The \fIpath\fR argument points to a remote machine and the link to that machine 182 is no longer active. 183 .RE 184 185 .sp 186 .ne 2 187 .na 188 \fB\fBENOTDIR\fR\fR 189 .ad 190 .RS 16n 191 A component of the \fIpath\fR prefix is not a directory or the provided 192 directory descriptor for \fBunlinkat()\fR is not \fBAT_FDCWD\fR or does not 193 reference a directory. 194 .RE 195 196 .sp 197 .ne 2 198 .na 199 \fB\fBEPERM\fR\fR 200 .ad 201 .RS 16n 202 The named file is a directory and {\fBPRIV_SYS_LINKDIR\fR} is not asserted in 203 the effective set of the calling process, or the filesystem implementation does 204 not support \fBunlink()\fR or \fBunlinkat()\fR on directories. 205 .RE 206 207 .sp 208 .ne 2 209 .na 210 \fB\fBEROFS\fR\fR 211 .ad 212 .RS 16n 213 The directory entry to be unlinked is part of a read-only file system. 214 .RE 215 216 .sp 217 .LP 218 The \fBunlink()\fR and \fBunlinkat()\fR functions may fail if: 219 .sp 220 .ne 2 221 .na 222 \fB\fBENAMETOOLONG\fR\fR 223 .ad 224 .RS 16n 225 Pathname resolution of a symbolic link produced an intermediate result whose 226 length exceeds {\fBPATH_MAX\fR}. 227 .RE 228 229 .sp 230 .ne 2 231 .na 232 \fB\fBETXTBSY\fR\fR 233 .ad 234 .RS 16n 235 The entry to be unlinked is the last directory entry to a pure procedure 236 (shared text) file that is being executed. 237 .RE 238 239 .SH USAGE 240 .sp 241 .LP 242 Applications should use \fBrmdir\fR(2) to remove a directory. 243 .SH ATTRIBUTES 244 .sp 245 .LP 246 See \fBattributes\fR(5) for descriptions of the following attributes: 247 .sp 248 249 .sp 250 .TS 251 box; 252 c | c 253 l | l . 254 ATTRIBUTE TYPE ATTRIBUTE VALUE 255 _ 256 Interface Stability T{ 257 \fBunlink()\fR is Standard; \fBunlinkat()\fR is Evolving 258 T} 259 _ 260 MT-Level Async-Signal-Safe 261 .TE 262 263 .SH SEE ALSO 264 .sp 265 .LP 266 \fBrm\fR(1), \fBclose\fR(2), \fBlink\fR(2), \fBopen\fR(2), \fBrmdir\fR(2), 267 \fBremove\fR(3C), \fBattributes\fR(5), \fBprivileges\fR(5), \fBfsattr\fR(5)