C/C++ Programmer's Guide (G06.25+)

Compiler Pragmas
HP C/C++ Programmer’s Guide for NonStop Systems—429301-008
13-38
FUNCTION
The pragma default settings are:
Usage Guidelines
•
The FUNCTION pragma can be entered on the compiler RUN command line or in
the source text. For TNS c89, the FUNCTION pragma must be entered in the
source file.
•
The alias attribute cannot be used with a pointer to a function.
•
The extensible and variable attributes cannot be specified for a function that
passes or returns a structure by value.
•
Only one language can be specified for a function.
•
FUNCTION can be entered in either uppercase or lowercase.
•
The extensible and variable attributes cannot both be specified for the same
function.
•
If you declare an external procedure as unspecified, then the actual procedure
cannot be both written in C and compiled using the OLDCALLS pragma.
•
Unlike previous methods for declaring external functions, the FUNCTION pragma is
compliant with the ISO/ANSI C standard.
•
The language attribute tal identifies both TAL and pTAL procedures.
•
The param-count argument for the extensible attribute can be used only for
native C and C++ programs.
•
Cfront imposes the following additional restrictions on the FUNCTION pragma:
°
It cannot be used for C++ functions or to change the language attribute.
°
It can be applied only to functions in the global scope.
°
No other pragmas can appear on the same line as a FUNCTION pragma.
°
The resident and alias attributes cannot be used.
•
C-style variable argument lists (...) cannot be used in variable and extensible
functions.
•
Extensible and variable functions in native C and C++ can have a maximum of 31
parameters.
•
Native C++ imposes the following additional restrictions on the FUNCTION pragma:
SYSTYPE GUARDIAN SYSTYPE OSS
TNS C compiler Not set Not set
G-series TNS c89 utility Not set Not set
TNS/R native C and C++ compilers Not set Not set
Native c89 utility Not set Not set
TNS/E native C and C++ compilers Not set Not set