This documentation is copyright © 1998-2001 Sandro Sigala <sandro@sigala.it>.
All rights reserved.
Released under the GNU General Public License.
tolower
Prototype
#include <ctype.h>
int tolower(int c);
Description
Returns the lowercase character corresponding to the character c
,
if the value of isupper
with the argument c
is true, otherwise returns
the c
argument unchanged.
Example
#include <ctype.h>
/*
* Compare the two strings ignoring the characters case.
*/
int istrcmp(const char *s1, const char *s2)
{
const unsigned char *sp1 = (const unsigned char *)s1;
const unsigned char *sp2 = (const unsigned char *)s2;
for (; tolower(*sp1) == tolower(*s2); ++sp1, ++sp2)
if (*sp1 == '\0')
return 0;
return tolower(*sp1) - tolower(*sp2);
}
References
ISO C 9899:1990 7.3.2.1