isdigit_l3

Usage

Library

Standard C Library (libc, -lc)

Overview

The isdigit() and isdigit_l() functions test for a decimal digit character. Regardless of locale, this includes the following characters only:

The isnumber() and isnumber_l() functions behave similarly to isdigit() and isdigit_l(), 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 _l-suffixed versions take an explicit locale argument, whereas the non-suffixed versions use the current global or per-thread locale.

Return values

The isdigit(), isdigit_l(), isnumber(), and isnumber_l() 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() or iswdigit_l() function should be used instead.