Pragma directives

A pragma is an implementation-defined instruction to the compiler. It has the general form:

Read syntax diagramSkip visual syntax diagram#pragma directive syntax
 
                        .--------------------.
                        V                    |
>>-#--pragma--+------+----character_sequence-+--new-line-------><
              '-STDC-'
 

The character_sequence is a series of characters giving a specific compiler instruction and arguments, if any. The token STDC indicates a standard pragma; consequently, no macro substitution takes place on the directive. The new-line character must terminate a pragma directive.

The character_sequence on a pragma is subject to macro substitutions. For example,

#define
XX_ISO_DATA
isolated_call(LG_ISO_DATA)
// ...
#pragma XX_ISO_DATA
Note:
You can also use the _Pragma operator syntax to specify a pragma directive; for details, see The _Pragma preprocessing operator .

More than one pragma construct can be specified on a single pragma directive. The compiler ignores unrecognized pragmas.

Standard C pragmas are described in Standard pragmas . IBM extension Pragmas available for XL C/C++ are described in "General purpose pragmas".