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TOLOWER(3) FreeBSD Library Functions Manual TOLOWER(3)
NAME
tolower, tolower_l - upper case to lower case letter conversion
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <ctype.h>
int
tolower(int c);
int
tolower_l(int c, locale_t loc);
DESCRIPTION
The tolower() 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 tolower_l() function takes an explicit locale argument, whereas the
tolower() function 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() or
towlower_l() function should be used instead.
SEE ALSO
ctype(3), ctype_l(3), islower(3), islower_l(3), towlower(3),
towlower_l(3), xlocale(3)
STANDARDS
The tolower() function conforms to ISO/IEC 9899:1990 ("ISO C90").
FreeBSD 14.0-RELEASE-p11 December 19, 2022 FreeBSD 14.0-RELEASE-p11