45 lines
881 B
C
45 lines
881 B
C
/*
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FUNCTION
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<<isalpha>>---alphabetic character predicate
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INDEX
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isalpha
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ANSI_SYNOPSIS
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#include <ctype.h>
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int isalpha(int <[c]>);
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TRAD_SYNOPSIS
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#include <ctype.h>
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int isalpha(<[c]>);
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DESCRIPTION
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<<isalpha>> is a macro which classifies ASCII integer values by table
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lookup. It is a predicate returning non-zero when <[c]> represents an
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alphabetic ASCII character, and 0 otherwise. It is defined only when
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<<isascii>>(<[c]>) is true or <[c]> is EOF.
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You can use a compiled subroutine instead of the macro definition by
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undefining the macro using `<<#undef isalpha>>'.
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RETURNS
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<<isalpha>> returns non-zero if <[c]> is a letter (<<A>>--<<Z>> or
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<<a>>--<<z>>).
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PORTABILITY
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<<isalpha>> is ANSI C.
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No supporting OS subroutines are required.
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*/
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#include <_ansi.h>
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#include <ctype.h>
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#undef isalpha
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int
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_DEFUN(isalpha,(c),int c)
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{
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return(__ctype_ptr__[c+1] & (_U|_L));
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}
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