Sample for pipe/inter-process communications on WIN?

[HPW]

For understanding the new function 'pipe' and 'process', is it possible to get some sample code which shows how to use it on windows?

[Lutz]

In the file 'qa' in the source distributin is a function  'test-pipe':

Code Select Expand


(define (test-pipe)
(write-file "pipe-child.lsp"
[text]
(set 'msg (read-line (integer (nth 2 (main-args)))))
(write-line (upper-case msg) (integer (nth 3 (main-args))))
(exit)
[/text]
)
(set 'channel (pipe))
(set 'in (first channel))
(set 'out (last channel))

(process (string "newlisp pipe-child.lsp " in " " out))
(sleep 300)
(write-line "hello there" out)
(sleep 100)
(= (read-line in) "HELLO THERE")
(delete-file "pipe-child.lsp"))


The child process will read a string and write back the uppercase via the pipe.



Lutz

[Lutz]

I just realize you should swap the last two lines, so the function only returns 'true' when succesfull:

Code Select Expand


(define (test-pipe)
(write-file "pipe-child.lsp"
[text]
(set 'msg (read-line (integer (nth 2 (main-args)))))
(write-line (upper-case msg) (integer (nth 3 (main-args))))
(exit)
[/text]
)
(set 'channel (pipe))
(set 'in (first channel))
(set 'out (last channel))

(process (string "newlisp pipe-child.lsp " in " " out))
(sleep 300)
(write-line "hello there" out)
(sleep 100)
(delete-file "pipe-child.lsp")
(= (read-line in) "HELLO THERE"))


Lutz

[HPW]

Interesting stuff.



On this matter I would have a wish for the 'process' command.



It it possible to add a flag 'Hidden' or something like that,

which would try to start the programm without a visible console

window.



In neobook the 'run' command has such option and I use

it successfully for starting the newLISP based UdpListener

in hidden mode. Then it only appears in the process-list

of the task-manager. So it is possible with newLISP-based apps.



With this it would be possible to start a invisble process from

a main-app and communicate with the pipe-function.

[Lutz]

newLISP is a console/shell application therefore you see a shell window popping up. If you do a (process "notepad.exe") you will see only the application window.



But isn't there some commandline parameter in Windows in do do this? the process function spawnvp()  I am using does not have such an option, but is compatible over all platforms supported.



Lutz

[HPW]

>But isn't there some commandline parameter in Windows in do do this?



Yes I think so. I am not sure that I can use them here with '!' or 'process'.

Will check.

But as I said I had start a newLISP console app hidden from neobook.

So there it works for sure.

[HPW]

I did not get it with '!' or 'process' but I looked in the WIN-API:

Code Select Expand


ShellExecute(0, 'open', 'ToStart.exe', 'CommandlineParams', 'StartDir' , SW_HIDE);


This works from a delphi-testapp.

[Lutz]

Thanks, hopefully it works with 'pipe'



Lutz

[Lutz]

This is how you can use it:



(set 'winexec (import "shell32.dll" "ShellExecuteA"))



(winexec 0 "open" "newlisp.exe" "" "" 0)  ; hides newlisp shell



(winexec 0 "open" "newlisp.exe" "" "" 1)  ; displays newlisp shell



(winexec 0 "open" "newlisp.exe" "" "" 2)  ; shell is minimized



The last two parameters before the mode number are command line parameters and startup directory the application assumes. here the original API:



HINSTANCE ShellExecute(



    HWND hwnd,   // handle to parent window

    LPCTSTR lpOperation,   // pointer to string that specifies operation to perform

    LPCTSTR lpFile,   // pointer to filename or folder name string

    LPCTSTR lpParameters,   // pointer to string that specifies executable-file parameters

    LPCTSTR lpDirectory,   // pointer to string that specifies default directory

    INT nShowCmd    // whether file is shown when opened

   );



Lutz



PS: I think it would not be a good idea to built this in to newLISP becuase there is no functional equivalent in Linux/Unix but the import gives you the full functionality offered by the Win32 API.

[pjot]

Hi,



I suffer the same type of problem when starting small scripts interpreted by an external binary. This is also the case with newLisp. I made a small "run.exe" which solves this issue. In there, I use CreateProcess:



//Start process without console window

si.dwFlags=STARTF_USESHOWWINDOW;

si.wShowWindow=SW_HIDE;

ret = CreateProcess (NULL, (char*)exe, NULL, NULL, FALSE,

      CREATE_NO_WINDOW, NULL, NULL, &si, &pi);



This will start the (interpreter-)process without DOS box. These are the specs according to the Win32 docs:



BOOL CreateProcess(



    LPCTSTR lpApplicationName,   // pointer to name of executable module

    LPTSTR lpCommandLine,   // pointer to command line string

    LPSECURITY_ATTRIBUTES lpProcessAttributes,   // pointer to process security attributes

    LPSECURITY_ATTRIBUTES lpThreadAttributes,   // pointer to thread security attributes

    BOOL bInheritHandles,   // handle inheritance flag

    DWORD dwCreationFlags,   // creation flags

    LPVOID lpEnvironment,   // pointer to new environment block

    LPCTSTR lpCurrentDirectory,   // pointer to current directory name

    LPSTARTUPINFO lpStartupInfo,   // pointer to STARTUPINFO

    LPPROCESS_INFORMATION lpProcessInformation    // pointer to PROCESS_INFORMATION  

   );





I use my "run.exe" also to start newLisp applications. I hope this helps. The "run.exe" can be found at my site.



Regards



Peter

[HPW]

PS: I think it would not be a good idea to built this in to newLISP because there is no functional equivalent in Linux/Unix but the import gives you the full functionality offered by the Win32 API.

Agree, no need for it. I had not thought about direct use of the API and it shows again the flexibility of newLISP. 2 lines of lisp and the freedom to use it either from EXE and DLL. Great.

[Lutz]

I remember several people on this board asked for exec without the window popping before. We should collect all these Win32 imports and put them together in a win32.lsp module. There is lots of other useful stuff in the Win23 API, just takes time to go thru it write the imports, document etc.



Lutz