Running custom commands with VS Code and CMake Tools

Question

I am using VS Code with the CMake Tools extension, and I would like to run a simple MPI program. Everything compiles just fine, and I can run my code in the terminal using

mpiexec -n 6 "path-to-my-workspace\build\my-executable.exe"

However, I would like to set things up so that this gets executed automatically when I press Control + Shift + P > "CMake: Run Without Debugging" (or Shift F5).

I read in the CMake Tools documentation that I could create new launch targets in a launch.json file. However, the VS Code documentation states that

The launch.json file is used to configure the debugger in Visual Studio Code.

I want this for debug, but also for release. Should I still use a launch.json file? I had the same problem in the past when I needed to pass arguments to my main function. What is the right way to do that in VS Code with CMake Tools?

Vengeful

you may be interested in the "tip" stated at code.visualstudio.com/docs/editor/debugging#_run-mode – Rhomb

Answer 1

This sounds like two cases of terminology-related confusion.

1. In VS Code, there are actions to "Run Code" and "Run Without Debugging". You can find more about the distinction between the two in this question. In a nutshell, "Run Code" runs the program inside a debugger program (like gdb), and and "Run Without Debugging" also runs the program, but doesn' run it inside a debugger program.

2. The two most common build modes are "debug" and "release", where debug includes debugging symbols that enable running in a debugger, and release does not and instead is built with more optimizations. VS Code can run both types of builds without debugging, and can run debug builds in a debugger. For release builds, it can only run outside a debugger.

You specify that you only care to run outside a debugger.

To answer your question "Should I still use a launch.json file?", yes, you can still use a launch.json file.

For running with a debugger, note that you can use the cmake.debugConfig setting, which will integrate with the features that CMake Tools provides for debugging targets.

Also, note:

Tip: The Run action is always available, but not all debugger extensions support 'Run'. In this case, 'Run' will be the same as 'Debug'.

Another note: If the program you wanted to run wasn't a build output of your project, then you would instead probably want to be using tasks.json.

If you like docs, see https://github.com/microsoft/vscode-cmake-tools/blob/main/docs/debug-launch.md.

Rhomb