tolower, tolower_l - transliterate uppercase characters to lowercase
#include <ctype.h> int tolower(int c); int tolower_l(int c, locale_t locale);
The tolower() and tolower_l() functions have as a domain a type int, the value of which is representable as an unsigned char or the value of EOF. If the argument has any other value, the argument is returned unchanged. The tolower() function operates in the current locale as set by setlocale(3C), while tolower_l() uses the locale represented by the locale argument.
If the argument of tolower() or tolower_l() represents an uppercase letter, and there exists a corresponding lowercase letter as defined by character type information in the locale category LC_CTYPE, the result is the corresponding lowercase letter. All other arguments in the domain are returned unchanged.
The behavior is undefined if the locale argument to tolower_l() is the special locale object LC_GLOBAL_LOCALE or is not a valid locale object handle.
On successful completion, tolower() and tolower_l() return the lowercase letter corresponding to the argument passed. Otherwise, they return the argument unchanged.
No errors are defined.
See attributes(7) for descriptions of the following attributes: