[haiku-3rdparty-dev] Re: Can Haiku emulate Amiga CLI/GUI startup?
- From: Michael Lotz <mmlr@xxxxxxxx>
- To: haiku-3rdparty-dev@xxxxxxxxxxxxx
- Date: Sun, 22 Feb 2015 10:47:39 +0100
Hi
On Feb 22, 2015 2:37 AM, Earl Pottinger <dmarc-noreply@xxxxxxxxxxxxx> wrote:
>
> ... Haiku-OS ...
Note that it's actually just called "Haiku"...
> Is there any way for a single Haiku-OS program to tell what environment
> invokes the progam
There are a couple of ways, not specific to Haiku, that you could use. None of
them are really perfect.
1: There's the isatty() POSIX function to determine if a file descriptor is a
terminal. You usually give it the file descriptor number of stdin or stdout (0
and 1 respectively according to POSIX). If stdin is connected to a TTY you
could assume the program to be running from a terminal. Note that redirecting
the std* FDs on the command line will throw this detection off, so if you
expect the program to be run with redirects this isn't a good method. I
actually haven't checked if this method works as expected under Haiku, but it
should.
2: Make a wrapper script that supplies an argument like "--gui" to your program
and use that in Deskbar or where you expect the user to click. This is a rather
clunky way to do it of course.
3: Make a symlink with a different name. If the command line version of your
program is called "myprogram" you could name the symlink for the GUI version
"MyProgram" for example. Then you can check the name that was used to invoke
the program by checking the (basename) value of argv[0] and vary the behaviour.
This is how some command line tools work (BusyBox exposes its commands like
this and determines which one was run by the name). You'd use the GUI symlink
in places like Deskbar as above. If a user renames your program or makes a
symlink to it with a different name, this approach will fail.
You could combine 1 and 3 to reduce the chances of misdetection.
Generally it might be considered confusing if a program changes behaviour based
on the environment, so making actually seperate programs might be better in any
case. To share code and reduce size, you could use a shared library from both
versions. Or make one call the other, like lpe does for Pe, which essentially
is what 2 does.
Regards,
Michael
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