#include <sicstus/sicstus.h> spio_t_error_code SP_unget_code( SP_stream *stream, int item);
Push back a character so it can be read again by subsequent read operations.
stream, e.g. with
SP_get_code(). As a special case, -1 can be put back if the last read operation returned end of file, i.e.,
On success, the character has been pushed back and will be read by the
next read operation.
SPIO_S_NOERR or some other success code is
On failure, returns an error code.
cpg-ref-SP_get_code. Prolog Streams.