Node:Writing User-stream Hooks, Next:, Up:Hookable Standard Streams

Writing User-stream Hooks

The user-stream hook is, if defined, called during SP_initialize(). It has the following prototype:

SP_stream *user_stream_hook(int which)

If the hook is not defined, SICStus will attempt to open the standard TTY/console versions of these streams. If they are unavailable (such as for windowed executables under Windows), the result is undefined.

It is called three times, one for each stream. The which argument indicates which stream it is called for. The value of which is one of:

Create stream for standard input.
Create stream for standard output.
Create stream for standard error.

The hook should return a standard SICStus I/O stream, as described in Defining a New Stream.