open/3¶

"open(+ F,+ M,- S" ) is iso

Opens the file with name _F_ in mode _M_ (read,writeorappend`), returning S unified with the stream name.

Yap allows 64 streams opened at the same time. If you need more, redefine the MaxStreams constant. Each stream is either an input or an output stream but not both. There are always 3 open streams: user_input for reading, user_output for writing and user_error for writing. If there is no ambiguity, the atoms user_input and user_output may be referred to as user.

The file_errors flag controls whether errors are reported when in mode read or append the file F does not exist or is not readable, and whether in mode write or append the file is not writable. `