Guardian C Library Calls Reference Manual

isascii (supplementary)
3-90 128833—Guardian TNS C Library Calls Reference Manual
Reference to Library Calls
isascii (supplementary)
The isascii function tests whether its argument is in the range 0 through 127.
character
specifies the character to test.
Return Value
is nonzero if character is in the range 0 through 127; otherwise, isascii returns the
value zero.
Usage Guidelines
•
The character-testing routine isascii 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.
•
The ISO/ANSI C standard does not specify isascii. However, the POSIX.1 standard
and XPG4 specification specify isascii.
#include <ctypeh>
int isascii(int character);