Sorry for the email necromancy, but since there are talks about post commit hooks again and as it seems it would generally be a useful feature, I remembered about the roadblock that Richard encountered that hadn't received a good anwser as far as I remember:
On Mon, Jan 3, 2011 at 12:58 PM, Richard Hipp <[email protected]> wrote: > > I've got a plan for a better way to do various "hooks", but in order for it > to work cross-platform, I need code that will start a background process on > windows. By "background" process, I mean a process that will continue > running even after its parent process exits or is killed. If any windows > experts out there can explain to me how to do that, or provide sample code, > that will expedite getting the "hook" logic into the Fossil trunk. So I looked into the win32 process creation APIs and played with them on a windows box. It turns out that CreateProcess (http://msdn.microsoft.com/en-us/library/ms682425%28v=vs.85%29.aspx) offers a range of options to run a process in a different console window, without a console, or with its stdin / stdout bound to arbitrary handles. If you look in the creation flags you can pass to CreateProcess (http://msdn.microsoft.com/en-us/library/ms684863(v=vs.85).aspx ), you can give CREATE_NEW_CONSOLE to create a new console window for the new process, CREATE_NO_WINDOW to have no window created for it, or DETACH_PROCESS to just detach the process (which seems different than CREATE_NO_WINDOW, I think it's for the case where you want to provide your own file handle for stdin and stdout, which I didn't try). Those three flags are mutually exclusive. Below is a quick test program I made that launch the file you give it on the command line. I used a small .bat file echoing things in a loop in both the console and a file for testing that I launched with it. With flags set at zero, predictably the script stopped running when I closed the console (but kept running after the program ended). With "CREATE_NEW_CONSOLE", it ran in a new, separate console window that kept running even when the original console was closed. With "CREATE_NO_WINDOW", it ran silently (the file kept growing) and kept running after closing the console (I had to kill it through the task manager). With "DETACHED_PROCESS", nothing happened. Obviously the script simply couldn't run without any form of input/output, but I suspect this is the option to use when you want to provide your own file handles to redirect stdin and stdout for the new process (in the STARTUPINFO structure). #include "stdafx.h" int _tmain(int argc, _TCHAR* argv[]) { //ShellExecute( NULL, "open", argv[1], NULL, NULL, 0 ); STARTUPINFO si; PROCESS_INFORMATION pi; ZeroMemory( &si, sizeof(si) ); si.cb = sizeof(si); ZeroMemory( &pi, sizeof(pi) ); CreateProcess( NULL, // No module name (use command line) argv[1], // Command line NULL, // Process handle not inheritable NULL, // Thread handle not inheritable FALSE, // Set handle inheritance to FALSE CREATE_NO_WINDOW, // No creation flags NULL, // Use parent's environment block NULL, // Use parent's starting directory &si, // Pointer to STARTUPINFO structure &pi ); // Pointer to PROCESS_INFORMATION structure return 0; } _______________________________________________ fossil-users mailing list [email protected] http://lists.fossil-scm.org:8080/cgi-bin/mailman/listinfo/fossil-users
