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