GB.tolower
int GB.tolower ( int c )
This is a locale insensitive replacement for the glibc
tolower() function.
You
must use this function instead of the standard glibc one to compare ASCII strings
in a case unsensitive way, because the glibc one is localization aware.
And if you did not know yet, in turkish,
strcasecmp("i", "I") != 0.
See also