diff options
Diffstat (limited to 'manual/intro.texi')
| -rw-r--r-- | manual/intro.texi | 56 |
1 files changed, 30 insertions, 26 deletions
diff --git a/manual/intro.texi b/manual/intro.texi index 382f35c039..b4cb344915 100644 --- a/manual/intro.texi +++ b/manual/intro.texi @@ -9,7 +9,7 @@ programs. @cindex library The GNU C library, described in this document, defines all of the -library functions that are specified by the ANSI C standard, as well as +library functions that are specified by the @w{ISO C} standard, as well as additional features specific to POSIX and other derivatives of the Unix operating system, and extensions specific to the GNU system. @@ -33,8 +33,8 @@ portability. This manual is written with the assumption that you are at least somewhat familiar with the C programming language and basic programming -concepts. Specifically, familiarity with ANSI standard C -(@pxref{ANSI C}), rather than ``traditional'' pre-ANSI C dialects, is +concepts. Specifically, familiarity with ISO standard C +(@pxref{ISO C}), rather than ``traditional'' pre-ISO C dialects, is assumed. The GNU C library includes several @dfn{header files}, each of which @@ -61,7 +61,7 @@ specific information about them. @cindex standards This section discusses the various standards and other sources that the -GNU C library is based upon. These sources include the ANSI C and +GNU C library is based upon. These sources include the @w{ISO C} and POSIX standards, and the System V and Berkeley Unix implementations. The primary focus of this manual is to tell you how to make effective @@ -77,44 +77,48 @@ other symbols provided by the library. This list also states which standards each function or symbol comes from. @menu -* ANSI C:: The American National Standard for the - C programming language. -* POSIX:: The IEEE 1003 standards for operating - systems. +* ISO C:: The international standard for the C + programming language. +* POSIX:: The ISO/IEC 9945 (aka IEEE 1003) standards + for operating systems. * Berkeley Unix:: BSD and SunOS. * SVID:: The System V Interface Description. @end menu -@node ANSI C, POSIX, , Standards and Portability -@subsection ANSI C -@cindex ANSI C +@node ISO C, POSIX, , Standards and Portability +@subsection ISO C +@cindex ISO C The GNU C library is compatible with the C standard adopted by the American National Standards Institute (ANSI): -@cite{American National Standard X3.159-1989---``ANSI C''}. +@cite{American National Standard X3.159-1989---``ANSI C''} and later +by the International Standardization Organizaion (ISO): +@cite{ISO/IEC 9899:1990, ``Programming languages---C''}. +We here refer to the standard as @w{ISO C} since this is the more +general standard in respect of ratification. The header files and library facilities that make up the GNU library are -a superset of those specified by the ANSI C standard.@refill +a superset of those specified by the @w{ISO C} standard.@refill @pindex gcc -If you are concerned about strict adherence to the ANSI C standard, you +If you are concerned about strict adherence to the @w{ISO C} standard, you should use the @samp{-ansi} option when you compile your programs with -the GNU C compiler. This tells the compiler to define @emph{only} ANSI +the GNU C compiler. This tells the compiler to define @emph{only} ISO standard features from the library header files, unless you explicitly ask for additional features. @xref{Feature Test Macros}, for information on how to do this. -Being able to restrict the library to include only ANSI C features is -important because ANSI C puts limitations on what names can be defined +Being able to restrict the library to include only @w{ISO C} features is +important because @w{ISO C} puts limitations on what names can be defined by the library implementation, and the GNU extensions don't fit these limitations. @xref{Reserved Names}, for more information about these restrictions. This manual does not attempt to give you complete details on the -differences between ANSI C and older dialects. It gives advice on how +differences between @w{ISO C} and older dialects. It gives advice on how to write programs to work portably under multiple C dialects, but does not aim for completeness. -@node POSIX, Berkeley Unix, ANSI C, Standards and Portability +@node POSIX, Berkeley Unix, ISO C, Standards and Portability @subsection POSIX (The Portable Operating System Interface) @cindex POSIX @cindex POSIX.1 @@ -128,8 +132,8 @@ Interface for Computer Environments}. POSIX is derived mostly from various versions of the Unix operating system. The library facilities specified by the POSIX standards are a superset -of those required by ANSI C; POSIX specifies additional features for -ANSI C functions, as well as specifying new additional functions. In +of those required by @w{ISO C}; POSIX specifies additional features for +@w{ISO C} functions, as well as specifying new additional functions. In general, the additional requirements and functionality defined by the POSIX standards are aimed at providing lower-level support for a particular kind of operating system environment, rather than general @@ -139,7 +143,7 @@ system environments.@refill The GNU C library implements all of the functions specified in @cite{IEEE Std 1003.1-1990, the POSIX System Application Program Interface}, commonly referred to as POSIX.1. The primary extensions to -the ANSI C facilities specified by this standard include file system +the @w{ISO C} facilities specified by this standard include file system interface primitives (@pxref{File System Interface}), device-specific terminal control functions (@pxref{Low-Level Terminal Interface}), and process control functions (@pxref{Processes}). @@ -175,7 +179,7 @@ The GNU C library defines facilities from some versions of Unix which are not formally standardized, specifically from the 4.2 BSD, 4.3 BSD, and 4.4 BSD Unix systems (also known as @dfn{Berkeley Unix}) and from @dfn{SunOS} (a popular 4.2 BSD derivative that includes some Unix System -V functionality). These systems support most of the ANSI and POSIX +V functionality). These systems support most of the @w{ISO C} and POSIX facilities, and 4.4 BSD and newer releases of SunOS in fact support them all. The BSD facilities include symbolic links (@pxref{Symbolic Links}), the @@ -193,7 +197,7 @@ the AT&T Unix System V operating system. It is to some extent a superset of the POSIX standard (@pxref{POSIX}). The GNU C library defines some of the facilities required by the SVID -that are not also required by the ANSI or POSIX standards, for +that are not also required by the @w{ISO C} or POSIX standards, for compatibility with System V Unix and other Unix systems (such as SunOS) which include these facilities. However, many of the more obscure and less generally useful facilities required by the SVID are @@ -295,7 +299,7 @@ program needs to include multiple header files, the order in which they are included doesn't matter. @strong{Compatibility Note:} Inclusion of standard header files in any -order and any number of times works in any ANSI C implementation. +order and any number of times works in any @w{ISO C} implementation. However, this has traditionally not been the case in many older C implementations. @@ -384,7 +388,7 @@ just makes your program slower. @cindex name space The names of all library types, macros, variables and functions that -come from the ANSI C standard are reserved unconditionally; your program +come from the @w{ISO C} standard are reserved unconditionally; your program @strong{may not} redefine these names. All other library names are reserved if your program explicitly includes the header file that defines or declares them. There are several reasons for these |