#include <string.h>
  void *memchr( const void *buffer, int ch, size_t count );

The memchr() function looks for the first occurrence of ch within count characters in the array pointed to by buffer. The return value points to the location of the first occurrence of ch, or NULL if ch isn't found. For example:

   char names[] = "Alan Bob Chris X Dave";
   if( memchr(names,'X',strlen(names)) == NULL )
     printf( "Didn't find an X\n" );
   else
     printf( "Found an X\n" );