c++ - Why does gcc have a warning for long long? -

what reason -wlong-long gcc warning?

from gcc man page:

-wlong-long        warn if long long type used.  enabled either -wpedantic or -wtraditional in iso c90 , c++98 modes.  inhibit warning messages, use -wno-long-long. 

as understand it, long long required @ least 64-bits (practically 64-bits, @ least today's compilers). not case iso c90 or c++98, or there other reason not use long long?

i know <stdint.h> types int64_t , friends, not-so-old compilers (e.g. vs2005, , green hills arm 3.5) not provide <stdint.h>, , thought long long (at least) 64 bits , newer toolchains.

there no long long type yet in iso c90 , c++98. has been added in iso c99 , c++11.

gcc provided extension prior standardization, though.