ISDIGIT(3) BSD Library Functions Manual ISDIGIT(3)NAME
isdigit, isnumber — decimal-digit character test
Standard C Library (libc, -lc)
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 characters, depending on the current locale setting.
The value of the argument must be representable as an unsigned char or
the value of EOF.
The isdigit() and isnumber() functions return zero if the character tests
false and return non-zero if the character tests true.
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 ALSOctype(3), iswdigit(3), multibyte(3), ascii(7)STANDARDS
The isdigit() function conforms to ISO/IEC 9899:1990 (“ISO C90”).
The isnumber() function appeared in 4.4BSD.
BSD May 4, 2007 BSD