Launching a program before Debugging in VSCode - debugging

Question

I am using VSCode 0.10.6 for C++ programming. I am trying to launch a program prior to debugging. The program, OpenOCD, is what GDB connects to. If I manually open and close it through a terminal, it works fine, but it seems like there should be an easy way to get VSCode to just start it for me.
I have played with tasks.json and it appears you need to use some ugly bat/sh files to accomplish this in combination with preLaunchTasks in launch.json.

Answer 1

Currently the answer is that you must indeed use preLaunchTasks to have a chance of making this work. I would have been happy to use an ugly script, if that indeed would work - but it doesn't. In my case, I needed one or more executables to be ran in the background, allowing VSCode to continue into debugging.
Unfortunately, each executable I tried to launch (via start) was not actually running as a "detached" process, and so VSCode would wait for each executable to finish running before it would finish the preLaunchTasks and start debugging. Not what I wanted.
I found an article by someone having a similar "detached process" problem with subversion, and I used his C++ code to solve this same issue with Visual Studio Code. I found a bug or two in that code, which I fixed. Here is what I'm currently using:
// dstart.cpp : Defines the entry point for the console application.
//
#include "stdafx.h"
#include <windows.h>
#include <stdio.h>
#include <tchar.h>
//http://stackoverflow.com/questions/1536205/running-another-program-in-windows-bat-file-and-not-create-child-process
//http://svn.haxx.se/users/archive-2008-11/0301.shtml
int _tmain()
{
//https://msdn.microsoft.com/en-us/library/windows/desktop/ms683156(v=vs.85).aspx
LPWSTR pCmd = ::GetCommandLine();
// skip the executable
if (*pCmd++ == L'"')
while (*pCmd++ != L'"');
else
while (*pCmd != NULL && *pCmd != L' ') ++pCmd;
while (*pCmd == L' ') pCmd++;
STARTUPINFO si;
ZeroMemory(&si, sizeof(si));
si.cb = sizeof(si);
PROCESS_INFORMATION pi;
ZeroMemory(&pi, sizeof(pi));
// Start the child process.
BOOL result = CreateProcess
(
NULL, // No module name (use command line)
pCmd, // Command line
NULL, // Process handle not inheritable
NULL, // Thread handle not inheritable
FALSE, // Set bInheritHandles to FALSE
CREATE_NEW_CONSOLE, // Detach process
NULL, // Use parent's environment block
NULL, // Use parent's starting directory
&si, // Pointer to STARTUPINFO structure
&pi // Pointer to PROCESS_INFORMATION structure (returned)
);
if (result) return 0;
wchar_t msg[2048];
FormatMessage
(
FORMAT_MESSAGE_FROM_SYSTEM,
NULL,
::GetLastError(),
MAKELANGID(LANG_NEUTRAL, SUBLANG_SYS_DEFAULT),
msg, sizeof(msg),
NULL
);
fputws(msg, stderr);
_flushall();
return -1;
}
Once compiled, you can use it similarly to how the start command works at a DOS prompt. Place that in the script you attach to your preLaunchTasks
in Visual Studio Code.