12.3.100 SP_unget_byte()

Synopsis

#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.

Arguments

stream

The stream. Must be a binary stream open for input.

item

The byte to push back. This must be the byte that was most recently read from 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., SPIO_E_END_OF_FILE.

Return Value

On success, the byte has been pushed back and will be read by the next read operation. SPIO_S_NOERR or some other success code is returned.

On failure, an error code is returned.

See Also

cpg-ref-SP_get_byte. Prolog Streams.