strstr.c revision 33965
1/* Simple implementation of strstr for systems without it. 2 This function is in the public domain. */ 3 4/* 5 6NAME 7 8 strstr -- locate first occurance of a substring 9 10SYNOPSIS 11 12 #include <string.h> 13 14 char *strstr (char *s1, char *s2) 15 16DESCRIPTION 17 18 Locates the first occurance in the string pointed to by S1 of 19 the string pointed to by S2. Returns a pointer to the substring 20 found, or a NULL pointer if not found. If S2 points to a string 21 with zero length, the function returns S1. 22 23BUGS 24 25*/ 26 27 28/* FIXME: The above description is ANSI compiliant. This routine has not 29 been validated to comply with it. -fnf */ 30 31char * 32strstr (s1, s2) 33 char *s1, *s2; 34{ 35 register char *p = s1; 36 extern char *strchr (); 37 extern int strncmp (); 38#if __GNUC__==2 39 extern __SIZE_TYPE__ strlen (); 40#endif 41 register int len = strlen (s2); 42 43 for (; (p = strchr (p, *s2)) != 0; p++) 44 { 45 if (strncmp (p, s2, len) == 0) 46 { 47 return (p); 48 } 49 } 50 return (0); 51} 52