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| author | rillig <rillig@pkgsrc.org> | 2006-10-06 21:44:30 +0000 |
|---|---|---|
| committer | rillig <rillig@pkgsrc.org> | 2006-10-06 21:44:30 +0000 |
| commit | 75c8628ae3cd3ce690f8e59f85c71db941841ebb (patch) | |
| tree | 42692533b2a5185fd2abe99d8a5b180b37faff3a /doc | |
| parent | 9dad87cbc2c365b0bc2364ee3a89672d47fd8ce0 (diff) | |
| download | pkgsrc-75c8628ae3cd3ce690f8e59f85c71db941841ebb.tar.gz | |
Added an introduction to feature test macros and tried to describe the
conditions under which getopt(3) is declared properly on Solaris, but
that's not easy.
Diffstat (limited to 'doc')
| -rw-r--r-- | doc/portability-book/files/functions.xml | 52 |
1 files changed, 46 insertions, 6 deletions
diff --git a/doc/portability-book/files/functions.xml b/doc/portability-book/files/functions.xml index 488c82b4aca..4b7f6d1bcd0 100644 --- a/doc/portability-book/files/functions.xml +++ b/doc/portability-book/files/functions.xml @@ -1,4 +1,4 @@ -<!-- $NetBSD: functions.xml,v 1.1.1.1 2006/10/06 21:10:41 rillig Exp $ --> +<!-- $NetBSD: functions.xml,v 1.2 2006/10/06 21:44:30 rillig Exp $ --> <chapter id="functions"> <title>C/C++: functions</title> @@ -6,11 +6,51 @@ <para>This chapter contains the requirements for using certain functions in C and C++ code.</para> +<sect1 id="feature"> +<title>Feature test macros</title> + +<para>When writing code that conforms to a specific standard, some +programmers may want to check that really only features from that +standard are used. For that purpose there exist a number of so-called +feature test macros that can be defined on the command line to the +compiler or in C and C++ source files before including any of the +standard include files.</para> + <table> +<title>Documentation of the feature test macros</title> +<tgroup cols="2"> +<thead> +<row><entry>Platform</entry><entry>Location</entry></row> +</thead> +<tbody> +<row><entry>SunOS-*-*</entry><entry><literal>standards(5)</literal></entry></row> +<row><entry>NetBSD-*-*</entry><entry><filename>/usr/include/sys/featuretest.h</filename></entry></row> +<row><entry>Linux-*-*</entry><entry><filename>/usr/include/features.h</filename></entry></row> +</tbody> +</tgroup> +</table> + +</sect1> + +<sect1 id="functions.byname"> <title>Functions on various platforms</title> -<tgroup cols="5"> + +<sect2 id="functions.getopt"> +<title>getopt</title> + +<para>Solaris provides the <function>getopt</function> function in three +of the standard headers: <stdio.h>, <stdlib.h> and +<unistd.h>, but the latter definition depends on other feature +test macros than the first two. Additionally, since Solaris 5.10, there +is also <getopt.h>, which provides +<function>getopt_long</function>, but not <function>getopt</function>. +The exact behavior also depends on the compiler. While SUNpro is quite +strict and requires the feature test macros, gcc finds the definition +without any of these macros. (TODO: Investigate further.)</para> + +<informaltable> +<tgroup cols="4"> <thead><row> - <entry>Function name</entry> <entry>Platform</entry> <entry>Library</entry> <entry>Headers</entry> @@ -19,14 +59,12 @@ in C and C++ code.</para> <tbody> <row> - <entry>getopt</entry> <entry>NetBSD-*-*</entry> <entry>c</entry> <entry>unistd.h</entry> <entry>_POSIX_C_SOURCE >= 2 || _XOPEN_SOURCE >= 4 || defined(_NETBSD_SOURCE)</entry> </row> <row> - <entry>getopt</entry> <entry>SunOS-5.10-*</entry> <entry>c</entry> <entry>unistd.h</entry> @@ -34,6 +72,8 @@ in C and C++ code.</para> </row> </tbody> </tgroup> -</table> +</informaltable> +</sect2> +</sect1> </chapter> |