| 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 | |
| 8 | Compares 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 | #ifdef __STDC__ |
| 17 | #include <stddef.h> |
| 18 | #else |
| 19 | #define size_t unsigned long |
| 20 | #endif |
| 21 | |
| 22 | int |
| 23 | strncmp(s1, s2, n) |
| 24 | const char *s1, *s2; |
| 25 | register size_t n; |
| 26 | { |
| 27 | register unsigned char u1, u2; |
| 28 | |
| 29 | while (n-- > 0) |
| 30 | { |
| 31 | u1 = (unsigned char) *s1++; |
| 32 | u2 = (unsigned char) *s2++; |
| 33 | if (u1 != u2) |
| 34 | return u1 - u2; |
| 35 | if (u1 == '\0') |
| 36 | return 0; |
| 37 | } |
| 38 | return 0; |
| 39 | } |