toupper, toupper_l - transliterate lower-case characters to upper-case
#include <ctype.h> int toupper(int c); int toupper_l(int c, locale_t locale);
The toupper() and toupper_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. If the argument of toupper() or toupper_l() represents a lower-case letter, and there exists a corresponding upper-case letter as defined by character type information in the current locale or in the locale represented by locale, respectively (category LC_CTYPE), the result is the corresponding upper-case letter. All other arguments in the domain are returned unchanged.
The behavior is undefined if the locale argument to toupper_l() is the special locale object LC_GLOBAL_LOCALE or is not a valid locale object handle.
On successful completion, toupper() and toupper_l() returns the upper-case letter corresponding to the argument passed.
No errors are defined.
See attributes(7) for descriptions of the following attributes: