Availability:C-language interface function
int Sclose(IOSTREAM 
*s)Close the stream. This first locks the stream (see PL_acquire_stream()). 
When successful it flushes pending output and calls the
Sclose_function() hook. Finally, the stream is unlocked and all 
memory associated to the stream is released. On success, the function 
returns 0. On failure a Prolog exception is raised and the return value 
is -1. Regardless of the return value, s becomes invalid 
after completion of Sclose(). 
See also Sgcclose().