NAME

isdigit — test for a decimal digit

SYNOPSIS

#include <ctype.h>

int isdigit(int c);

DESCRIPTION

The isdigit() function tests whether c is a character of class digit in the program's current locale, see the XBD specification, Locale .

In all cases c is an int, the value of which must be a character representable as an unsigned char or must equal the value of the macro EOF. If the argument has any other value, the behaviour is undefined.

RETURN VALUE

The isdigit() function returns non-zero if c is a decimal digit; otherwise it returns 0.

ERRORS

No errors are defined.

EXAMPLES

None.

APPLICATION USAGE

To ensure applications portability, especially across natural languages, only this function and those listed in the SEE ALSO section should be used for character classification.

FUTURE DIRECTIONS

None.

SEE ALSO

isalnum(3) , isalpha(3) , iscntrl(3) , isgraph(3) , islower(3) , isprint(3) , ispunct(3) , isspace(3) , isupper(3) , isxdigit(3) , <ctype.h> .

DERIVATION

Derived from Issue 1 of the SVID.