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6.47. Pragmas Accepted by GCC

GCC supports several types of pragmas, primarily in order to compile code originally written for other compilers. Note that in general we do not recommend the use of pragmas; Section 6.25 Declaring Attributes of Functions, for further explanation.

6.47.1. RS/6000 and PowerPC Pragmas

The RS/6000 and PowerPC targets define one pragma for controlling whether or not the longcall attribute is added to function declarations by default. This pragma overrides the -mlongcall option, but not the longcall and shortcall attributes. Section 4.17.1 IBM RS/6000 and PowerPC Options, for more information about when long calls are and are not necessary.

longcall (1)

Apply the longcall attribute to all subsequent function declarations.

longcall (0)

Do not apply the longcall attribute to subsequent function declarations.

6.47.2. Darwin Pragmas

The following pragmas are available for all architectures running the Darwin operating system. These are useful for compatibility with other Mac OS compilers.

mark tokens

This pragma is accepted, but has no effect.

options align=alignment

This pragma sets the alignment of fields in structures. The values of alignment may be mac68k, to emulate m68k alignment, or power, to emulate PowerPC alignment. Uses of this pragma nest properly; to restore the previous setting, use reset for the alignment.

segment tokens

This pragma is accepted, but has no effect.

unused (var [, var]…)

This pragma declares variables to be possibly unused. GCC will not produce warnings for the listed variables. The effect is similar to that of the unused attribute, except that this pragma may appear anywhere within the variables' scopes.

 
 
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