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islower
[lower-case character predicate]

SYNOPSIS
#include <ctype.h>
int islower(int c);

DESCRIPTION
islower is a macro which classifies ASCII integer values by table lookup. It is a predicate returning non-zero for minuscules (lower-case alphabetic characters), and 0 for other characters. It is defined only when isascii(c) is true or c is EOF.

You can use a compiled subroutine instead of the macro definition by undefining the macro using #undef islower.

RETURNS
islower returns non-zero if c is a lower case letter (a–z).

COMPLIANCE
islower is ANSI C.

No supporting OS subroutines are required.