libiberty/strncmp.c

   1 /* strncmp -- compare two strings, stop after n bytes.
   2    This function is in the public domain.  */
   3
   4 /*
   5
   6 @deftypefn Supplemental int strncmp (const char *@var{s1}, @
   7   const char *@var{s2}, size_t @var{n})
   8
   9 Compares the first @var{n} bytes of two strings, returning a value as
  10 @code{strcmp}.
  11
  12 @end deftypefn
  13
  14 */
  15
  16 #include <ansidecl.h>
  17 #include <stddef.h>
  18
  19 int
  20 strncmp(const char *s1, const char *s2, register size_t n)
  21 {
  22   register unsigned char u1, u2;
  23
  24   while (n-- > 0)
  25     {
  26       u1 = (unsigned char) *s1++;
  27       u2 = (unsigned char) *s2++;
  28       if (u1 != u2)
  29         return u1 - u2;
  30       if (u1 == '\0')
  31         return 0;
  32     }
  33   return 0;
  34 }