HP C/iX Library Reference Manual (30026-90004)

218 Chapter5
HP C/iX Library Function Descriptions
isdigit
isdigit
Tests whether an argument is a decimal digit.
Syntax
#include <ctype.h>
int isdigit (int c );
Parameters
c An argument to be evaluated. The argument must be representable as an
unsigned char or the macro EOF.
Return Values
≠0 The argument passed in c is a decimal digit.
0 The argument passed in
c is not a decimal digit.
Description
The isdigit function returns a nonzero value if the argument passed in c is a decimal
digit (ASCII characters 0 through 9); otherwise, the returned value is zero.
See Also
isalnum(), isalpha(), iscntrl(), isgraph(), islower(), isprint(), ispunct(),
isspace(), isupper(), isxdigit(), ANSI C 4.3.1.4, POSIX.1 8.1