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/*
FUNCTION
<<isalpha>>, <<isalpha_l>>---alphabetic character predicate
INDEX
isalpha
INDEX
isalpha_l
SYNOPSIS
#include <ctype.h>
int isalpha(int <[c]>);
#include <ctype.h>
int isalpha_l(int <[c]>, locale_t <[locale]>);
DESCRIPTION
<<isalpha>> is a macro which classifies singlebyte charset 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 if
<[c]> is representable as an unsigned char or if <[c]> is EOF.
<<isalpha_l>> is like <<isalpha>> but performs the check based on the
locale specified by the locale object locale. If <[locale]> is
LC_GLOBAL_LOCALE or not a valid locale object, the behaviour is undefined.
You can use a compiled subroutine instead of the macro definition by
undefining the macro using `<<#undef isalpha>>' or `<<#undef isalpha_l>>'.
RETURNS
<<isalpha>>, <<isalpha_l>> return non-zero if <[c]> is a letter.
PORTABILITY
<<isalpha>> is ANSI C.
<<isalpha_l>> is POSIX-1.2008.
No supporting OS subroutines are required.
*/
#include <_ansi.h>
#include <ctype.h>
#undef isalpha
int
isalpha (int c)
{
return(__CTYPE_PTR[c+1] & (_U|_L));
}
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