ref: f06d16d9edba690a5938c3a8d3863f0c817f2fad
dir: /sys/src/libString/s_tolower.c/
#include <u.h>
#include <libc.h>
#include "String.h"
/* convert String to lower case */
void
s_tolower(String *sp)
{
char *cp;
for(cp=sp->ptr; *cp; cp++)
*cp = tolower(*cp);
}