Name
strnstr — 
     Find the first substring in a length-limited string
 
Synopsis
char * strnstr ( | const char * s1,  | 
|   | const char * s2,  | 
|   | size_t len); | 
 
Arguments
s1
     The string to be searched
    
s2
     The string to search for
    
len
     the maximum number of characters to search