Redirecting output from command prompt and saving it to an array?

[mjed]

Hello everyone,

I have a program that executes a file, and have used the following code to run the file:

int exec=0;

LaunchExecutableEx ("cmd.exe /c config.exe parameters ", LE_HIDE, &exec); 

When the config.exe is ran, it generates output on the command screen which I would like to redirect and store in an array. Is this possible?

I am trying to avoid redirecting the output to a file and storing it from there.

Thanks!

[edjones93]

Hi!

Could you elaborate on why this is needed? The current methodology I can see working is using pipes, this is discussed in the below linked stackoverflow thread:

https://stackoverflow.com/questions/1404189/how-to-read-redirect-output-of-a-dos-command-to-a-progra...

Although I believe popen would only redirect the settings when the pipe is closed. To get continual data I would try looking into the first suggestion of passing a STARTUPINFO structure with the handles. There is a microsoft example from first glance:

https://support.microsoft.com/en-us/help/190351/how-to-spawn-console-processes-with-redirected-stand...

Hopefully this will help provide a solution,

Ed

[mjed]

Hello Ed,

Thanks for the response. I've tried using popen but it doesn't seem to be supported in LabWindows. Whenever I try to compile the program, it doesn't recognize that function. Do you have any idea why? 

Thanks! 

[edjones93]

You will need to include the headers for this Windows function which is included in the requirements section for the MSDN page:

https://msdn.microsoft.com/en-us/library/96ayss4b.aspx

[mjed]

I've included all the required headers, and still get this message:

20, 17 error: implicit declaration of function '_popen' is invalid in C99. Make sure that you include the function prototype.

Thanks again for all your help I really appreciate it! 

[edjones93]

These issues are C and Win32 based and not explicitly LabWindows/ANSI C, the solution is to declare the function as described in the below thread:

https://stackoverflow.com/questions/15850042/xcode-warning-implicit-declaration-of-function-is-inval...

Therefore include just after your header declaration and before main, the line:

FILE *_popen(  
const char *command,  
const char *mode   
);  

[mjed]

So I tried that, and then I received this error:

error: Undefined symbol '__pclose' referenced in "c:\Users\mjj\Desktop\test\cvibuild.test\Debug\test.obj".

error: Undefined symbol '__popen' referenced in "c:\Users\mj\Desktop\test\cvibuild.test\Debug\test.obj".

Is there a library I have to include? 

Thanks again for your help and your fast responses!

[mjed]

I was unable to get _popen to work, but ended up finding a code someone had written that performed exactly what I wanted to do, and it works great. Below is the link to that code:

https://cboard.cprogramming.com/windows-programming/65209-encapsulating-cmd-exe.html?highlight=creat...

Thanks again for all the help!