armode | noarmode (C only) (IBM extension)

When the METAL compiler option is in effect, you can use the armode function attribute to specify whether or not a given function is to operate in access-register (AR) mode. AR mode allows a C function to access multiple additional data spaces, and manipulate more data in memory.


armode function attribute syntax

>>-__attribute__--((--+-armode---+--))-------------------------><
                      '-noarmode-'

Functions in AR mode can call functions not in AR mode, and vice versa.

The following example declares the function foo to be in AR mode:

void foo() __attribute__((armode));

The attribute overrides the default setting of the ARMODE compiler option for the specified function. Note that this attribute is only supported when the METAL compiler option is in effect.

For more information on ARMODE and METAL compiler options, see ARMODE and METAL compiler options in the z/OS® XL C/C++ User's Guide.