tolower
—
upper case to lower case letter conversion
Standard C Library (libc, -lc)
#include <ctype.h>
int
tolower
(int
c);
The tolower
() function converts an upper-case letter to
the corresponding lower-case letter. The argument must be representable as an
unsigned char or the value of
EOF
.
If the argument is an upper-case letter, the tolower
()
function returns the corresponding lower-case letter if there is one;
otherwise, the argument is returned unchanged.
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
() function should be used
instead.
The tolower
() function conforms to
ISO/IEC 9899:1990 (“ISO C90”).