Description

The isalnum() function tests for any character for which [isalpha()|int isalpha(int c)] or [isdigit()|int isdigit(int c)] is true.

The behavior of the isalnum() function is affected by the current locale. To modify the behavior, change the LC_CTYPE category in setlocale(), that is, setlocale(LC_CTYPE, newlocale). In the C locale or in a locale where character type information is not defined, characters are classified according to the rules of the U.S. ASCII 7-bit coded character set.

Parameters

• c Is an integer whose value is representable as an unsigned char or the value of the macro EOF.

Return Values

The isalnum() function returns non-zero for true and zero for false. If the parameter is not in the domain of the function, the return result is undefined.