isalpha
[alphabetic character predicate]
SYNOPSIS
#include
<ctype.h>
int isalpha(int
c);
DESCRIPTION
isalpha
is a macro which classifies ASCII integer
values by table lookup. It is a predicate returning non-zero when c
represents an alphabetic ASCII character,
and 0 otherwise. 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 isalpha.
RETURNS
isalpha
returns non-zero if c
is a letter (A–Z
or a–z).
COMPLIANCE
isalpha
is ANSI C.
No supporting OS subroutines are required.
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