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ISDIGIT(3) |
Library Functions Manual |
ISDIGIT(3) |
NAME
isdigit — decimal-digit character test
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <ctype.h>
int
isdigit(int c);
DESCRIPTION
The isdigit() function tests for any decimal-digit character.
RETURN VALUES
The isdigit() function returns zero if the character tests false and returns non-zero if the character tests true.
SEE ALSO
ctype(3),
isalnum(3),
isalpha(3),
isascii(3),
isblank(3),
iscntrl(3),
isgraph(3),
islower(3),
isprint(3),
ispunct(3),
isspace(3),
isupper(3),
isxdigit(3),
stdio(3),
toascii(3),
tolower(3),
toupper(3),
ascii(7)
STANDARDS
The isdigit() function conforms to ANSI X3.159-1989 (“ANSI C89”).
CAVEATS
The argument to
isdigit() must be
EOF or representable as an
unsigned char; otherwise, the behavior is undefined. See the
CAVEATS section of
ctype(3) for more details.