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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 characters, depending on the current locale setting. For single C chars locales (see multibyte(3)), the value of the argument is 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 August 21, 2004 BSD |