如何在 Visual Studio Code 中使用 Cgo 调试 Go

Question

I can set breakpoints and step through the Go code without issues in Visual Studio Code if there is no Cgo code. Once Cgo code is called in the Go code, breakpoints are basically ignored, although the application runs fine.

Here is the snippet:

//hello.c
#include <stdio.h>

void Test() {
  printf("C: Hello world");
}

//hello.go
package main

// #cgo LDFLAGS: -Wl,--allow-multiple-definition
// #cgo CFLAGS: -Wall -std=c99 -O1 -g
/*
#include "hello.c"
*/
import "C"

import "fmt"

func main() {
    //Call to void function without params
    C.Test()
    fmt.Printf("Go: Hello world\n")
}

//launch.json
{
    // Use IntelliSense to learn about possible attributes.
    // Hover to view descriptions of existing attributes.
    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
    "version": "0.2.0",
    "configurations": [
        {
            "name": "Launch Package",
            "type": "go",
            "request": "launch",
            "mode": "debug",
            "program": "learning"
        }
    ]
}

Answer 1

Currently I am facing this exact bug. If you time.Sleep at the beginning

func main() {

    time.Sleep(time.Hour) //now hover on your breakpoints
    
    //Call to void function without params
    C.Test()
    fmt.Printf("Go: Hello world\n")
}

you can see the breakpoints are hollow. Only information I can get is from the tooltip at that states

could not find the file c:\d\e\main.go

I can only reproduce this on windows. Might be because windows uses \\ for it's paths but c compiler or dlv-dap or go can't tell if it's a windows path. Because in most programs \\ is an escape character. Normally path separators are escaped using \\\\. Windows currently supports both forward and backslashes except sometimes it doesn't work. To my knowledge cgo debugging is working normally with UNIX alike systems that uses / on file paths. This is probably underlying bug that you can't solve by changing the terminal.

This might not be an option but you could try linux or macos.

Answer 2

This is currently a known bug . This may get fixed in go 1.7.4. You can normally debug on Linux.