12.3.20 SP_fopen()

Synopsis

#include <sicstus/sicstus.h>

spio_t_error_code
SP_fopen(
  char const *pathname,
  void *reserved,
  spio_t_bits options,
  SP_stream **pstream);

Opens a file and creates a SICStus stream reading and/or writing to it.

Arguments

pathname

The path to the file as an encoded string. It is expanded by SP_expand_file_name() unless the option SP_FOPEN_OPTION_NOEXPAND is specified, in which case the path must already have been expanded by SP_expand_file_name().

reserved

Reserved, should be NULL.

read_options

The following bits can be set:

SP_FOPEN_OPTION_READ

Open the file for reading. The file must exist.

SP_FOPEN_OPTION_WRITE

Open the file for writing. The file is overwritten if it exists. The file is created if it does not exist.

SP_FOPEN_OPTION_APPEND

Open the file for writing but start writing at the end of the file if it exists. The file is created if it does not exist.

SP_FOPEN_OPTION_BINARY

Open the file as a binary (byte) stream.

SP_FOPEN_OPTION_TEXT

Open the file as a text stream. The default character encoding is Latin 1 (i.e. the 8 bit subset of Unicode). The default end of line convention is OS specific.

SP_FOPEN_OPTION_AUTOFLUSH

After writing to this stream, Prolog predicates will do a flush_output/1. In essence this ensures that the stream behaves as if it were unbuffered.

SP_FOPEN_OPTION_INTERACTIVE

Treat this stream as an interactive stream. Implies SP_CREATE_STREAM_OPTION_AUTOFLUSH.

SP_FOPEN_OPTION_NO_FSYNC

If this is set, flush and close of the stream will not wait for data to reach the disk. See the SP_fclose() option SP_FCLOSE_OPTION_NO_FSYNC for more information.

SP_FOPEN_OPTION_NOEXPAND

The pathname has already been expanded with SP_expand_file_name() or something similar. This implies that pathname is an absolute path. If this option is not specified, pathname is expanded with SP_expand_file_name() before use.

pstream

On successful return, *pstream will be set to the created stream.

Return Value

On success, *pstream will be set to the created stream and SPIO_S_NOERR or some other success code returned.

On failure, some SPIO failure code will be returned. Error codes with special meaning for SP_fopen():

SPIO_E_FILE_NOT_FOUND

The file does not exist.

SPIO_E_FILE_ACCESS

Insufficient permissions to open or create the file.

SPIO_E_OPEN_ERROR

Generic error during open.

Other error codes may also be returned.

See Also

Prolog Streams.