Question

I’m writing a program with C++ and by native Win32 API. I’m creating a process from a SFX archive EXE in silent mode that no GUI is shown to user. But I want to show a progress bar in my application, while the SFX archive extracting.

How can I do that?

Thanks.

Answer 1

If the process you create produces some textual output to the standard output then you can probably parse that output somehow and show the progress. To know if it does, activate it in a command line windows and watch what you get from it.

win32’s CreateProcess() allows you to redirect the standard output of the process to a pipe. This way you can receive the output as soon as it is produced.

If the process you’re creating doesn’t report its progress somehow then there’s really not much you can do. You can try to come up with function between the size of the file and the average time it takes to extract it and then fake a progress bar. That will serve the purpose of setting the user’s mind at ease but nothing more.

—Edit
The call to CreateProcess() returns as soon as the process is created. CreateProcess() fills up the struct PROCESS_INFORMATION with the handles of the process it creates. it contains the handle of the main thread of the process. If you want to wait for the process to finish you can WaitForSingleEvent() on that thread handle which gets signaled when the thread terminates. Don’t forget to CloseHandle() those handles when you’re done with them.