Kari Laine ha scritto:
I got interested this writing process input thing. I can read process output without problem. Although it seems that reading of the stdout will start only when process ends. I made a little filter program in C and a gambas project to try to use it but I can not get the wrriting work so that when written the filter would return something to gambas-project. This got to do something that same program cannot both write and read to process - or what? Well here they are if someone is also interested to test. I would be very great full for any advice how to write to certain process.
If you look carefully at the docs about EXEC:[ _Process_ *=* ] *EXEC* _Command_ [ *WAIT* ] [ *FOR* { { *READ* | *INPUT* } | { *WRITE* | *OUTPUT* } } ] [ *AS* _Name_ ]
you'll notice that you can't specify both READ & WRITE --------^I have also a big book about Linux programming and, when I first read that book, I was wondered because it said that you can't open a pipe both for reading and for writing. Doing such things is a completely different matter, it said. Still I think that it should be possible with the right calls but, don't knowing what gambas does behind the scenes, the only thing I can say now, is that the syntax explanation does not permit that. But gambas happily lets you specify both READ & WRITE...
Then, reading more carefully, I noticed that the docs say: "if you specify INPUT & OUTPUT instead of READ & WRITE, then the process is executed inside a virtual terminal". Remembering that that book was talking, if I well remember, about virtual terminals to be necessary to do such things, I tried in gambas. And it works!
I attach the project, which uses "tr" as filter.Run it, then click ToggleButton1; in the gambas console you will see what the program sends to tr, and in the textarea you will see what tr replies back to the program.
Cheers.
doublepipe-0.0.1.tar.gz
Description: application/tgz
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