| _tolower | Function (Macro)

ctype.h

short _tolower (short c);

Translates uppercase characters to lowercase.

_tolower does the same conversion as tolower or toextlower, except that it should be used only when c is known to be uppercase (either ordinary or foreign). It is faster, and generates much shorter code than tolower. _tolower returns the converted value of c if it is uppercase; otherwise, the result is undefined. _tolower is a simple macro.