tolower
---translate characters to lower case#include <ctype.h> int tolower(int c); int _tolower(int c);Description
tolower
is a macro which converts upper-case characters to lower
case, leaving all other characters unchanged. It is only defined when
c is an integer in the range EOF
to 255
.
You can use a compiled subroutine instead of the macro definition by
undefining this macro using `#undef tolower
'.
_tolower
performs the same conversion as tolower
, but should
only be used when c is known to be an uppercase character (A
--Z
).
Returns
tolower
returns the lower-case equivalent of c when it is a
character between A
and Z
, and c otherwise.
_tolower
returns the lower-case equivalent of c when it is a
character between A
and Z
. If c is not one of these
characters, the behaviour of _tolower
is undefined.
Portability
tolower
is ANSI C. _tolower
is not recommended for portable
programs.
No supporting OS subroutines are required.