.\" Copyright (c) 1998 HD Associates, Inc. .\" All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .\" $FreeBSD: src/share/man/man9/posix4.9,v 1.5.2.5 2001/08/17 13:08:54 ru Exp $ .\" $DragonFly: src/share/man/man9/posix4.9,v 1.3 2004/03/11 12:28:57 hmp Exp $ .Dd March 1, 1998 .Dt POSIX.1B 9 .Os .Sh NAME .Nm posix1b .Nd "Posix P1003-1B extensions" .Sh DESCRIPTION POSIX.1B adds real time extensions and some commonly used Berkeley extensions to POSIX.1. This section contains preliminary information about avoiding conflicts and adding support for the required ability to specify the interface version. .Sh STATUS March 28, 1998: _POSIX_PRIORITY_SCHEDULING works with these kernel options in your configuration: .Bd -literal -offset 0i options "P1003_1B" options "_KPOSIX_PRIORITY_SCHEDULING" .Ed .Sh SPECIFYING THE VERSION There are three manifest constants that set the version and programming interface for POSIX.1B. .Bd -literal -offset 0i _POSIX_VERSION .Ed specifies the system for which the system is built. The default is POSIX.1 and is 199009L. POSIX.1B is 199309L. This defines the base features of the operating system. .Bd -literal -offset 0i _POSIX_SOURCE .Ed is a macro from POSIX.1 that can be defined to specify that only POSIX and ANSI functionality should occur in the name space. .Bd -literal -offset 0i _POSIX_C_SOURCE .Ed is a macro from POSIX.1B that can be defined to specify that only POSIX and ANSI functionality from a specific POSIX version should occur in the name space, i.e., if _POSIX_VERSION is 199309L (POSIX.1B) but _POSIX_C_SOURCE is 199009L (POSIX.1) then only POSIX.1 features should appear. .Sh PROPERLY HIDING EXTENSIONS The following test macros are set up in . They should used by system header files to avoid the kind of tests you see in . Source programs should not use these .Dx specific implementation details and should test _POSIX_VERSION, _POSIX_SOURCE and _POSIX_C_SOURCE. These should not be used in the kernel though - the kernel should be immune to the user land setting of _POSIX_VERSION. The P1003_1B option can be used in the kernel to limit inclusion of new code, but make sure things work properly when a POSIX.1B program is run on a kernel without the P1003_1B option. .Bd -literal -offset 0i _P1003_1B_VISIBLE .Ed is a test macro that sorts out when extensions should be visible. It is defined in . .Pp In normal C program development only _POSIX_VERSION is set, permitting .Bx extensions to appear to the programs. However, when adding new functionality mandated by POSIX.1B, it is important to satisfy the requirements added by the new _POSIX_C_SOURCE macro. _P1003_1B_VISIBLE (not a standard feature test macro) is defined in sys/unistd.h when the combination of _POSIX_VERSION, _POSIX_SOURCE, and _POSIX_C_SOURCE indicate that the extensions are in scope. .Bd -literal -offset 0i _P1003_1B_VISIBLE_HISTORICALLY .Ed is present to conditionalize POSIX.1B extensions that were historically in the system. These are visible when _POSIX_SOURCE and _POSIX_C_SOURCE are not set at all or when _POSIX_C_SOURCE enables POSIX.1B features. The intent of this feature test is to permit hiding the new extensions while still letting .Bx extensions show up to avoid breaking existing programs without trying to use the "big hammer" of _POSIX_C_SOURCE. .Pp Some recent additions to header files are new enough that they should be changed to be dependent on _P1003_1B_VISIBLE instead of _HISTORICALLY. .Pp Traditional .Bx headers (e.g., mmap.h) now specified in POSIX.1B can include and conditionalize .Bx extensions on _P1003_1B_VISIBLE_HISTORICALLY. .Sh NON STANDARD TEST MACROS .Bd -literal -offset 0i _P1003_1B_INCLUDE_MAYBES .Ed when set before the inclusion of any other header file requests that all header files that the POSIX.1B spec says a standard header may include should be included. Normally no non-required headers are included. Setting this pre-processor definition should make any compliant program compile without issues of header file inclusion. .Bd -literal -offset 0i P1003_1B .Ed is a config option to build in POSIX.1B support in the kernel. .\" .Sh SEE ALSO .Sh HISTORY The .Nm section manual page appeared in .Fx 3.0 .