ISDIGIT(3) | Library Functions Manual | ISDIGIT(3) |
isdigit
, isdigit_l
— decimal-digit single-byte character
test
#include
<ctype.h>
int
isdigit
(int
c);
int
isdigit_l
(int
c, locale_t
locale);
The
isdigit
()
and
isdigit_l
()
functions test for any decimal-digit character. The complete list of decimal
digits is 0 and 1–9, in any locale.
These functions return zero if the character tests false or non-zero if the character tests true.
On systems supporting non-ASCII single-byte character encodings,
different c arguments may correspond to the digits,
and the results of isdigit
() may depend on the
LC_CTYPE
locale(1).
isalnum(3), isalpha(3), isascii(3), isblank(3), iscntrl(3), isgraph(3), islower(3), isprint(3), ispunct(3), isspace(3), isupper(3), iswdigit(3), isxdigit(3), stdio(3), toascii(3), tolower(3), toupper(3), ascii(7)
The isdigit
() function conforms to
ANSI X3.159-1989 (“ANSI C89”),
and isdigit_l
() to IEEE Std
1003.1-2008 (“POSIX.1”).
The isdigit
() function first appeared in
Version 7 AT&T UNIX, and
isdigit_l
() has been available since
OpenBSD 6.2.
The argument c must be
EOF
or representable as an unsigned
char
; otherwise, the result is undefined.
September 5, 2017 | OpenBSD-current |