Description
int 
ftok ( string pathname, string proj )
     The function converts the pathname of an existing
     accessible file and a project identifier (proj)
     into a
     integer for use with for example
     shmop_open() and other System V IPC keys. The
     proj parameter should be a one character string.
    
     On success the return value will be the created key value, otherwise 
     -1 is returned.
    
     See also shmop_open() and sem_get().