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