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[binutils.git] / libiberty / strncmp.c
blobad87e1fde8ba704aa7ca64f9ca3b9cb8e157a268
1 /* strncmp -- compare two strings, stop after n bytes.
2 This function is in the public domain. */
4 /*
6 @deftypefn Supplemental int strncmp (const char *@var{s1}, const char *@var{s2}, size_t @var{n})
8 Compares the first @var{n} bytes of two strings, returning a value as
9 @code{strcmp}.
11 @end deftypefn
15 #include <ansidecl.h>
16 #ifdef ANSI_PROTOTYPES
17 #include <stddef.h>
18 #else
19 #define size_t unsigned long
20 #endif
22 int
23 strncmp(s1, s2, n)
24 const char *s1, *s2;
25 register size_t n;
27 register unsigned char u1, u2;
29 while (n-- > 0)
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;
38 return 0;