Description
The isalpha() function tests for any character for which
isupper(int c) or
int islower(int c) is true, or any
character that is one of an implementation-defined set of characters for
which none of
int iscntrl(int c),
int isdigit(int c),
int ispunct(int c), or
int isspace(int c)is true. In the C locale, isalpha() returns true only for the characters for which
int isupper(int c) or
int islower(int c) is true.
The behavior of the isalpha() 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 isalpha() 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.