Guardian C Library Calls Reference Manual

toupper
3-226 128833—Guardian TNS C Library Calls Reference Manual
Reference to Library Calls
toupper
The toupper function determines the uppercase equivalent of a lowercase letter.
character
is the character whose uppercase equivalent you desire.
Return Value
is the uppercase equivalent of character.
Usage Guidelines
•
If character is not a lowercase letter, toupper simply returns it unchanged.
•
The character-testing routine toupper is implemented as a macro, but the C compiler
provides an underlying function with the same name as the macro. Although the
macro is faster than the function, it evaluates its argument more than once.
Consequently, if you need to provide an expression with side effects as the argument
to this routine, you should undefine the macro so that the C compiler uses the
function instead. For more information about undefining macros, refer to the C/C++
Programmer’s Guide.
#include <ctypeh>
int toupper(int character);