A child process gets a terminal on Windows by attaching to a
pseudo console. The Epilog window (see swipl-win.exe)
has no console of its own: it talks to its Prolog thread over two pipes,
and a child handed those has nothing that echoes what it reads, no
window size and no way to be interrupted. The functions below put such a
child on the console of the terminal behind a stream. This is what shell/1
does, and what process_create/3
does for the streams the caller left alone. They exist on Windows only.
- HANDLE Swinpseudoconsole(IOSTREAM
*s)
- Claim the pseudo console of the terminal behind s, or
NULL if it has none to give. This is a claim rather than a
query: the console reads and writes the same pipe ends as the stream, so
the terminal runs one only while a client holds it, and the holder must
touch neither the stream nor its companions meanwhile. Declared
HANDLE because HPCON postdates SWI-Stream.h;
they are the same.
- void Swinrelease_pseudoconsole(IOSTREAM
*s)
- Hand the console back once the child is gone. The terminal closes it
when the last client has released it.
- void * Swinpseudoconsole_attributes(HANDLE
hpcon)
- Process attribute list that puts a child on hpcon, or
NULL if it cannot be built. Pass it as the
lpAttributeList of a STARTUPINFOEXW and create
the process with EXTENDED_STARTUPINFO_PRESENT. Not with
CREATE_NO_WINDOW: that asks for a console of the child's
own, which is the opposite of what the attribute says and wins.
- void Swinfree_pseudoconsole_attributes(void
*attributes)
- Free the list once the child is created. The console itself is held
until Swinrelease_pseudoconsole().
