NAME
tolower, tolower_l
— upper case to lower case
letter conversion
LIBRARY
library “libc”
SYNOPSIS
#include
<ctype.h>
int
tolower(int
c);
int
tolower_l(int
c, locale_t
locale);
DESCRIPTION
Thetolower()
and
tolower_l()
functions convert an upper-case letter to the corresponding lower-case letter.
The argument must be representable as an unsigned char
or the value of EOF.
The _l-suffixed version takes an explicit locale argument, whereas the non-suffixed version uses the current global or per-thread locale.
RETURN VALUES
If the argument is an upper-case letter, the
tolower() and tolower_l()
functions return the corresponding lower-case letter if there is one;
otherwise, the argument is returned unchanged.
COMPATIBILITY
The 4.4BSD extension of accepting
arguments outside of the range of the unsigned char
type in locales with large character sets is considered obsolete and may not
be supported in future releases. The towlower() and
towlower_l() functions should be used instead.
SEE ALSO
ctype(3), ctype_l(3), islower(3), towlower(3), towlower_l(3), xlocale(3)
STANDARDS
The tolower() function conforms to
ISO/IEC 9899:1990 (“ISO C90”).
The tolower_l() function conforms to
IEEE Std 1003.1-2008 (“POSIX.1”).