Re: Problem when executing application from batch file

Some people have mentioned that if the user started multiple copies of the
App almost simoultenously, PrevInstance will not return the correct
information. Maybe you are witnessing that. The solution is to use a Mutex,
however, you could have problems with terminal servers because a Mutex is
usually system wide, while PrevInstance is session wide. If you use a fixed
global Mutex string, only 1 copy of your App will run per computer. Usually
you could use "Local\" prefix to avoid this problem, but it seems that it's
not supported in NT 4.0 according to CreateMutex() function.

To support NT4, you could create a global mutex, like "MyApp-1", which
includes your App's EXE name and the session ID returned by
ProcessIdToSessionId() API function. You will need to check the OS version
since this function requires NT4+SP4 and above.

Look for "vb CreateMutex" in newsgroups for samples.

Obtaining Windows' Version Information
http://vbnet.mvps.org/index.html?code/system/getversionex.htm



"Someone" <nobody@xxxxxxx> wrote in message
news:hgI0f.320$MN6.220@xxxxxxxxxxxxx
>> Only the first batch line is executed when my app is not running
>
> I can't see your code, so I can only speculate. I think that your app
> maybe executing 4 times, but your the logic that checks for PrevInstance
> maybe terminating the App without further processing. There maybe
> something you have overlooked. Again, I can't see your code. To be sure
> whether your App runs once or 4 times, use a message box at the very
> begging of Main. Example:
>
> MsgBox "Main called, PrevInstance = " & App.PrevInstance
>
> If you see 4 copies of the MsgBox, then the batch file is executing as
> expected and you could go to the next step...
>
>
> "Jack" <replyto@newsgroup> wrote in message
> news:%23YcBf9VyFHA.3812@xxxxxxxxxxxxxxxxxxxxxxx
>>I appreciate your help.
>> We are close but not close enough.
>> My batch file has 4 lines.
>> Only the first batch line is executed when my app is not running, but
>> command prompt widow shows all batch lines processed(?)
>> At least there is not any error indication and there is not any
>> interruption in batch processing.
>> Jack
>> "Someone" <nobody@xxxxxxx> wrote in message
>> news:iFH0f.314$MN6.228@xxxxxxxxxxxxx
>>> Use this instead:
>>>
>>> start "MyTitle" "<path>test.exe" /55512340453
>>>
>>> When "start" sees the first quote, it treats it as a window title.
>>> Apparently this is only supported in XP and most likely Windows 2000.
>>> Windows 9x does not support the title option. If you use quotes around
>>> the path and don't include any option, then you have to use the title
>>> option as well. Here are some valid examples:
>>>
>>> start "" "<path>test.exe" /55512340453
>>> start /i "<path>test.exe" /55512340453
>>> start /normal "<path>test.exe" /55512340453
>>>
>>> Here is what Windows 95/98 show:
>>>
>>> Runs a Windows program or MS-DOS program.
>>>
>>> START [options] program [arg...]
>>> START [options] document.ext
>>>
>>> /m[inimized] Run the new program minimized (in the background).
>>> /max[imized] Run the new program maximized (in the background).
>>> /r[estored] Run the new program restored (in the foreground).
>>> [default]
>>> /w[ait] Does not return until the other program exits.
>>>
>>>
>>>
>>>
>>> "Jack" <replyto@newsgroup> wrote in message
>>> news:eCNTxkVyFHA.2212@xxxxxxxxxxxxxxxxxxxxxxx
>>>>I tried your suggestion.
>>>> When I used start followed by file name followed by traling parameter
>>>> Windows complain about that trailing parameter.
>>>> my line looks like that:
>>>> start "<path>test.exe" /55512340453
>>>> Jack
>>>>
>>>> "Someone" <nobody@xxxxxxx> wrote in message
>>>> news:b0H0f.304$MN6.236@xxxxxxxxxxxxx
>>>>> To force the batch file to not wait for your app and return
>>>>> immediately, use "start" without the /wait option. For example, I made
>>>>> a test.bat with the following:
>>>>>
>>>>> project1
>>>>> project1
>>>>> project1
>>>>>
>>>>> This executed 1 copy at a time, each taking 10 seconds to run because
>>>>> the loop I had in Main. When I changed the batch file to the
>>>>> following:
>>>>>
>>>>> start Project1
>>>>> start Project1
>>>>> start Project1
>>>>>
>>>>> The 3 copies were executed almost simultaneously, and 3 Project1.exe
>>>>> appeared in Task Manager each using about %33 of CPU time. The prompt
>>>>> returned immediately before they finished executing.
>>>>>
>>>>> Using "start" this way insures consistent behavior if your OS happens
>>>>> to behave differently.
>>>>>
>>>>>
>>>>>
>>>>> "Jack" <replyto@newsgroup> wrote in message
>>>>> news:eBfB3EVyFHA.3312@xxxxxxxxxxxxxxxxxxxxxxx
>>>>>>I am confused about your suggestion.
>>>>>> My app primary task is not accepting commands from the batch file.
>>>>>> It is a big, universal app, and one of the added (on request)
>>>>>> features is to accept commands from a batch file.
>>>>>> When commands are incoming my app is not smart enough to know whether
>>>>>> it is a single command from command prompt or it is part of batch
>>>>>> file execution. As a consequence of that I cannot just ignore
>>>>>> checking for previous instance. I have to do that to avoid multiple
>>>>>> instances.
>>>>>> Hope it clears up a little.
>>>>>> Jack
>>>>>> "Someone" <nobody@xxxxxxx> wrote in message
>>>>>> news:iaG0f.292$MN6.75@xxxxxxxxxxxxx
>>>>>>> It appears that outside a batch file, i.e., in Command Prompt, the
>>>>>>> app is started and you are returned to the "C:\" prompt immediately.
>>>>>>> In a batch file it waits for the App to finish before going to the
>>>>>>> next line, so checking for previous instance is not necessary. If
>>>>>>> you are at Command Prompt and wanted to type the EXE name and wait
>>>>>>> till the program finishes, use:
>>>>>>>
>>>>>>> start /wait yourapp /para1 /para2...
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> "DanS" <t.h.i.s.n.t.h.a.t@xxxxxxxxxxxxxxxxxxxxxx> wrote in message
>>>>>>> news:Xns96E5DB32A2E19idispcom@xxxxxxxxxxxxxxxxx
>>>>>>>> "Jack" <replyto@newsgroup> wrote in
>>>>>>>> news:evhDSZUyFHA.464@xxxxxxxxxxxxxxxxxxxx:
>>>>>>>>
>>>>>>>>> I do not understand and maybe someone please can explain to why,
>>>>>>>>> after
>>>>>>>>> executing the first line of the batch file the batch execution
>>>>>>>>> stops
>>>>>>>>> until I close my application.
>>>>>>>>> What kind of mechanism is that?
>>>>>>>>> sample of batch file:
>>>>>>>>> [].exe /5553331234
>>>>>>>>> [].exe /5556770808
>>>>>>>>> [].exe /5553451234
>>>>>>>>>
>>>>>>>>> That happens only if there is not previous instance running.
>>>>>>>>> I can see batch execution in CMD window. I can see the first batch
>>>>>>>>> line being executed and then nothing. I close my app and then
>>>>>>>>> second
>>>>>>>>> line of batch file appears and my app is alive again. I close my
>>>>>>>>> app
>>>>>>>>> and then the third line of batch file will appear.
>>>>>>>>> If I understand the mechanism of that behaviour maybe I can patch
>>>>>>>>> over
>>>>>>>>> that problem
>>>>>>>>> Jack
>>>>>>>>>
>>>>>>>>
>>>>>>>> Is that 3 seperate lines in the batch file ?
>>>>>>>>
>>>>>>>> In the OP, I thought by accept multiple command line params I
>>>>>>>> thought you
>>>>>>>> meant like: program.exe /param1 /param2 /param3
>>>>>>>>
>>>>>>>> The batch file acts exactly as it was intended. It runs the first
>>>>>>>> line,
>>>>>>>> waits until that program ends, then runs the next line.
>>>>>>>>
>>>>>>>> I would have written the command$ handler to parse the string and
>>>>>>>> look for
>>>>>>>> multiple params, which is what I thought you did, and you wouldn't
>>>>>>>> have had
>>>>>>>> this issue.
>>>>>>>>
>>>>>>>> Regards,
>>>>>>>>
>>>>>>>> DanS
>>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>
>>>
>>
>>
>
>


.

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