Error while using command prompt or shell using process_create/3 in SWI Prolog

Question

On Windows 7, when I used process_create/3 in SWI Prolog to open an application like Notepad.exe, the notepad opens. However, it doesn't work for applications that use command prompt. As an example, when I tried to open the command prompt window, using:

main :- process_create('C:\\WINDOWS\\system32\\cmd.exe',[] ,[]).

which gives an

ERROR: Process "c:\windows\system32\cmd.exe": exit status: 1

Similarly, when trying it to open powershell.exe, it doesn't work either. the console just hangs, without displaying an error.

Any help is greatly appreciated.

Do you need to start the application so that you start using it instead of the Prolog program currently running? Without additional arguments, process_create/3 is used for running a non-interactive program once. If you want to switch focus you might want to read carefully through all of the options you can pass to process_create/3. — user1812457
From my Prolog code, I am trying to start the application which is a .bat that starts a command prompt window and starts running in it. You need to pass arguments to it. Now I am able to run the application from my code using win_exec/2 and it works too(including passing parameters to it). But I wanted to run it using process_create/3 passing arguments to it by passing them in the Args list as explained in the documentation. However, it doesn't work. So I tried to open Notepad.exe and cmd.exe to see how it works, as explained above. Any idea on how to make it work? Thanks. — shujin
For the time being you might be better off using win_exec/2. I don't use Windows so the best I can do to help you is to read the documentation more carefully than you ;) but it seems that process_create/3 is not as useful as win_exec/2 for Windows. Don't take my word though. — user1812457

Grzegorz Adam Kowalski Grzegorz Adam Kowalski · Accepted Answer · 2016-07-07T12:46:10

To start a separate console window:

?- process_create(path(cmd), ['/c', 'start', 'cmd'], []).

Or even shorter (but I don't know how portable this is):

?- process_create(path(cmd), ['/c', 'start'], []).

Or this way (idea taken from SWI-Prolog source code):

?- getenv('COMSPEC', CMD), process_create(CMD, ['/c', 'start'], []).

To start an external BAT command with 3 arguments:

?- process_create(
    path(cmd), 
    ['/c', 'start', 'cmd', '/c', 'c:\\test\\test.bat', 'arg1', 'arg2', 'arg3'],
    []).

Important note: theoretically you could pass all this arguments as one string, eg. '/c start cmd ...' instead of list of strings but strange things may happen in more sophisticated cases. In my case SWI-Prolog 7.2.3 added single quote or single double quote at the end, so the last argument passed to batch script was not arg3 but arg3' or arg3".

Error while using command prompt or shell using process_create/3 in SWI Prolog

1 Answers