56 lines
1.3 KiB
C
56 lines
1.3 KiB
C
/*
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FUNCTION
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<<tolower>>---translate characters to lower case
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INDEX
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tolower
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INDEX
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_tolower
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ANSI_SYNOPSIS
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#include <ctype.h>
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int tolower(int <[c]>);
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int _tolower(int <[c]>);
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TRAD_SYNOPSIS
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#include <ctype.h>
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int tolower(<[c]>);
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int _tolower(<[c]>);
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DESCRIPTION
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<<tolower>> is a macro which converts upper-case characters to lower
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case, leaving all other characters unchanged. It is only defined when
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<[c]> is an integer in the range <<EOF>> to <<255>>.
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You can use a compiled subroutine instead of the macro definition by
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undefining this macro using `<<#undef tolower>>'.
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<<_tolower>> performs the same conversion as <<tolower>>, but should
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only be used when <[c]> is known to be an uppercase character (<<A>>--<<Z>>).
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RETURNS
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<<tolower>> returns the lower-case equivalent of <[c]> when it is a
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character between <<A>> and <<Z>>, and <[c]> otherwise.
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<<_tolower>> returns the lower-case equivalent of <[c]> when it is a
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character between <<A>> and <<Z>>. If <[c]> is not one of these
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characters, the behaviour of <<_tolower>> is undefined.
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PORTABILITY
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<<tolower>> is ANSI C. <<_tolower>> is not recommended for portable
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programs.
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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 tolower
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int
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_DEFUN(tolower,(c),int c)
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{
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return isupper(c) ? (c) - 'A' + 'a' : c;
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}
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