blob: 60902ea40ee80b513a525f9403728398ea876d7e [file] [log] [blame]
/* Simple implementation of strstr for systems without it.
This function is in the public domain. */
@deftypefn Supplemental char* strstr (const char *@var{string}, const char *@var{sub})
This function searches for the substring @var{sub} in the string
@var{string}, not including the terminating null characters. A pointer
to the first occurrence of @var{sub} is returned, or @code{NULL} if the
substring is absent. If @var{sub} points to a string with zero
length, the function returns @var{string}.
@end deftypefn
/* FIXME: The above description is ANSI compiliant. This routine has not
been validated to comply with it. -fnf */
#include <stddef.h>
extern char *strchr (const char *, int);
extern int strncmp (const void *, const void *, size_t);
extern size_t strlen (const char *);
char *
strstr (const char *s1, const char *s2)
const char *p = s1;
const size_t len = strlen (s2);
for (; (p = strchr (p, *s2)) != 0; p++)
if (strncmp (p, s2, len) == 0)
return (char *)p;
return (0);