#pragma options [no]longlong
Allows IBM long long integer types in your program.
-qlonglong for the xlc,
xlc++, xlC, cc and c99 invocation commands; -qnolonglong for
the c89 invocation command.
-qlonglong
This
option takes effect when the -qlanglvl=extended | stdc89
| extc89 option is in effect. It is not valid when the -qlanglvl=stdc99
| extc99 option is in effect, because the long long support
provided by this option is incompatible with the semantics of the long
long types mandated by the C99 standard.
This option does not take effect when the -qlanglvl=c99longlong option
is in effect, because the long long support provided
by this option is incompatible with the semantics of the long
long types mandated by the C99 standard as adopted in C++0x.
_LONG_LONG is defined to 1 when long long data types are available; otherwise, it is undefined.
cc myprogram.c -qlonglong