NAME

DESCRIPTION

DEFINITIONS

The null character is a character with value 0, conventionally represented in the C language as \0. A character array is a sequence of characters. A null-terminated character array (a string) is a sequence of characters, the last of which is the null character. The null string is a character array containing only the terminating null character. A null pointer is the value that is obtained by casting 0 into a pointer. C guarantees that this value will not match that of any legitimate pointer, so many functions that return pointers return NULL to indicate an error. The macro NULL is defined in <stdio.h>. Types of the form size_t are defined in the appropriate headers.

MULTITHREADED APPLICATIONS

The libpthread(3LIB) and libthread(3LIB) libraries are implemented as filters on libc(3LIB).

When compiling a multithreaded application, the -mt option must be specified on the command line.

There is no need for a multithreaded application to link with -lthread. An application must link with -lpthread only when POSIX semantics for fork(2) are desired. When an application is linked with -lpthread, a call to fork() assumes the behavior fork1(2) rather than the default behavior that forks all threads.

When compiling a POSIX-conforming application, either the _POSIX_C_SOURCE or _POSIX_PTHREAD_SEMANTICS option must be specified on the command line. For POSIX.1c-conforming applications, define the _POSIX_C_SOURCE flag to be >= 199506L:

cc -mt [ flag... ] file... -D_POSIX_C_SOURCE=199506L -lpthread

For POSIX behavior with the Solaris fork() and fork1() distinction, compile as follows:

cc -mt [ flag... ] file... -D_POSIX_PTHREAD_SEMANTICS

For Solaris threads behavior, compile as follows:

cc -mt [ flag... ] file...

Unsafe interfaces should be called only from the main thread to ensure the application's safety.

MT-Safe interfaces are denoted in the ATTRIBUTES section of the functions and libraries manual pages (see attributes(5)). If a manual page does not state explicitly that an interface is MT-Safe, the user should assume that the interface is unsafe.

REALTIME APPLICATIONS

FILES

LIBDIR

LIBDIR/*.so

ACKNOWLEDGMENTS

The Institute of Electrical and Electronics Engineers and The Open Group, have given us permission to reprint portions of their documentation.

In the following statement, the phrase ``this text'' refers to portions of the system documentation.

Portions of this text are reprinted and reproduced in electronic form in the SunOS Reference Manual, from IEEE Std 1003.1, 2004 Edition, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2004 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between these versions and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/online.html.

This notice shall appear on any product containing this material.

SEE ALSO

Linker and Libraries Guide

Performance Profiling Tools

ANSI C Programmer's Guide

DIAGNOSTICS

NOTES

The headers in INCDIR provide function prototypes (function declarations including the types of arguments) for most of the functions listed in this manual. Function prototypes allow the compiler to check for correct usage of these functions in the user's program. The lint program checker can also be used and will report discrepancies even if the headers are not included with #include statements. Definitions for Sections 2 and 3C are checked automatically. Other definitions can be included by using the -l option to lint. (For example, -lm includes definitions for libm.) Use of lint is highly recommended. See the lint chapter in Performance Profiling Tools

Users should carefully note the difference between STREAMS and stream. STREAMS is a set of kernel mechanisms that support the development of network services and data communication drivers. It is composed of utility routines, kernel facilities, and a set of data structures. A stream is a file with its associated buffering. It is declared to be a pointer to a type FILE defined in <stdio.h>.

In detailed definitions of components, it is sometimes necessary to refer to symbolic names that are implementation-specific, but which are not necessarily expected to be accessible to an application program. Many of these symbolic names describe boundary conditions and system limits.

In this section, for readability, these implementation-specific values are given symbolic names. These names always appear enclosed in curly brackets to distinguish them from symbolic names of other implementation-specific constants that are accessible to application programs by headers. These names are not necessarily accessible to an application program through a header, although they can be defined in the documentation for a particular system.

In general, a portable application program should not refer to these symbolic names in its code. For example, an application program would not be expected to test the length of an argument list given to a routine to determine if it was greater than {ARG_MAX}.