Libft(17) - isdigit

Libft(17) - isdigit

 

ISDIGIT(3)               BSD Library Functions Manual               ISDIGIT(3)

NAME
     isdigit, isnumber -- decimal-digit character test

LIBRARY
     Standard C Library (libc, -lc)

SYNOPSIS
     #include <ctype.h>

     int
     isdigit(int c);

     int
     isnumber(int c);

DESCRIPTION
     The isdigit() function tests for a decimal digit character.  Regardless of locale, this
     includes the following characters only:

     ``0''         ``1''         ``2''         ``3''         ``4''
     ``5''         ``6''         ``7''         ``8''         ``9''

     The isnumber() function behaves similarly to isdigit(), but may recognize additional char-
     acters, depending on the current locale setting.

     The value of the argument must be representable as an unsigned char or the value of EOF.

RETURN VALUES
     The isdigit() and isnumber() functions return zero if the character tests false and return
     non-zero if the character tests true.

COMPATIBILITY
     The 4.4BSD extension of accepting arguments outside of the range of the unsigned char type
     in locales with large character sets is considered obsolete and may not be supported in
     future releases.  The iswdigit() function should be used instead.

SEE ALSO
     ctype(3), isalnum_l(3), iswdigit(3), multibyte(3), ascii(7)

STANDARDS
     The isdigit() function conforms to ISO/IEC 9899:1990 (``ISO C90'').

HISTORY
     The isnumber() function appeared in 4.4BSD.

BSD                               May 4, 2007                              BSD

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