stdsyms.5 (2010 09)

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stdsyms(5) stdsyms(5)
NAME
stdsyms - description of named defines and other specifications for namespace from HP-UX header files
DESCRIPTION
stdsyms is a description of "named defines" and other specifications that must be set by the application
to obtain the appropriate namespace from the HP-UX header files.
HP-UX header files are organized in a manner that allows for only a subset of the symbols available in
that header file to be visible to an application that conforms to a specific standard. The ANSI-C,
POSIX.1, POSIX.2, XPG4 and subsequent enhanced versions of ANSI-C/POSIX/XPG each reserve a cer-
tain set of symbols for that standard’s namespace. In addition, the HP-UX implementation of XPG3 and
the "OSF AES/OS" provides for a clean namespace although this is not a specific requirement of those
standards.
The following rules apply in determining what symbols are reserved for any standard. These symbols are
reserved for the standard and for use by the implementation, and must be either avoided altogether, or
used exactly as defined by the specified standard.
• All symbols defined by the desired standard are reserved. Refer to the appropriate standards docu-
mentation for a complete list of reserved symbols.
• All symbols beginning with an underscore followed by another underscore or an uppercase letter are
reserved for the implementation.
• All external identifiers beginning with an underscore are reserved for the implementation.
The following is a list of feature test macros which must be defined to obtain the appropriate namespace
from the header files.
__STDC__ This symbol is automatically defined by the ANSI-C preprocessor and is
automatically defined when specifying an ANSI-C compile (cc -Aa). Using
the strict ANSI option -Aa requests a pure ANSI-C namespace, which is the
smallest subset of the HP-UX namespace available. The -Aa option also
enables the inclusion of ANSI-C-style function prototypes for increased type
checking. Note that the default namespace when using the -Aa option is the
ANSI-C namespace; therefore a broader namespace must be requested if it is
desired.
__STDC_VERSION__
This symbol is automatically defined by the ANSI-C preprocessor on some
implementations. If defined, it indicates the version of the standard it is com-
plying with.
_POSIX_SOURCE As documented in the IEEE POSIX.1 standard, the programmer is required to
define the _POSIX_SOURCE
feature test macro to obtain the POSIX.1
namespace and POSIX.1 functionality. This feature test macro can be defined,
either by using compiler options (
-D_POSIX_SOURCE
) or by using #define
directives in the source files before any #include directives. Note that the
default POSIX namespace is the POSIX.1-1990 namespace. It is necessary to
define the _POSIX1_1988 feature test macro in addition to the
_POSIX_SOURCE macro in order to obtain the POSIX.1-1988 namespace.
_POSIX_C_SOURCE As documented in the IEEE POSIX.2 standard, the programmer is required to
define the _POSIX_C_SOURCE feature test macro with a value of 2 to obtain
the POSIX.1 and POSIX.2 namespaces and functionality. This feature test
macro can be defined, either by using compiler options
(-D_POSIX_C_SOURCE=2) or by using #define directives in the source
files before any #include directives.
_XOPEN_SOURCE As documented in the X/Open Portability Guide (XPG), the programmer is
required to define the _XOPEN_SOURCE feature test macro to obtain X/Open
functionality. This feature test macro can be defined, either by using compiler
options (-D_XOPEN_SOURCE) or by using #define directives in the source
files before any #include directives. Although XPG3 does not specify any
namespace pollution rules, XPG4 and its subsequent versions have instituted
such rules. Therefore, the HP-UX operating system provides clean
namespaces whenever _XOPEN_SOURCE is defined.
HP-UX 11i Version 3: September 2010 − 1 − Hewlett-Packard Company 1