VS Code — Compile Multiple C/C++ Files in One Directory

This post covers how to compile multiple C/C++ source files that live in the same directory using a single VS Code build task — no Makefile required.

Environment: Visual Studio Code (any recent version), gcc / g++ installed and on PATH

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[01] The Problem — Single-File vs. Multi-File Compilation

By default, VS Code’s C/C++ quick-build shortcuts compile only the currently open file (${file}). When a project is split across several .cpp or .c files in one directory, that produces linker errors because the other translation units are never passed to the compiler.

Example — two-file project:

project/
├── main.cpp      ← entry point, calls helper()
└── helper.cpp    ← defines helper()

Compiling only main.cpp fails:

/tmp/ccXXXX.o: undefined reference to `helper()'
collect2: error: ld returned 1 exit status

The fix is to pass project/*.cpp to the compiler — and VS Code’s Variables Reference makes this easy to express without hard-coding the path.

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[02] Variables Reference

VS Code exposes a set of predefined variables that can be used inside tasks.json, launch.json, and settings.json. The two variables used in this recipe are:

Variable	Expands to
${fileDirname}	Absolute path of the directory containing the currently open file
${fileExtname}	Extension of the currently open file (e.g., .cpp)
${file}	Absolute path of the currently open file
${fileBasenameNoExtension}	Filename without path or extension — used as the output binary name
${workspaceRoot}	Absolute path of the workspace root folder

Combining the first two: "${fileDirname}/*${fileExtname}" expands to something like /home/user/project/*.cpp — exactly what the compiler needs.

Full variable list: VS Code Variables Reference

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[03] Writing tasks.json

Place tasks.json inside .vscode/ at your workspace root. The file below defines three build tasks and one run task.

{
    "version": "2.0.0",
    "runner": "terminal",
    "type": "shell",
    "echoCommand": true,
    "presentation": { "reveal": "always" },
    "tasks": [
        {
            "label": "save_and_compile_for_C++-groups",
            "command": "g++",
            "args": [
                "${fileDirname}/*${fileExtname}",
                "-o",
                "${fileDirname}/${fileBasenameNoExtension}"
            ],
            "group": "build",
            "problemMatcher": {
                "fileLocation": ["relative", "${workspaceRoot}"],
                "pattern": {
                    "regexp": "^(.*):(\\d+):(\\d+):\\s+(warning|error):\\s+(.*)$",
                    "file": 1,
                    "line": 2,
                    "column": 3,
                    "severity": 4,
                    "message": 5
                }
            }
        },
        {
            "label": "save_and_compile_for_C++-single",
            "command": "g++",
            "args": [
                "${file}",
                "-o",
                "${fileDirname}/${fileBasenameNoExtension}"
            ],
            "group": "build",
            "problemMatcher": {
                "fileLocation": ["relative", "${workspaceRoot}"],
                "pattern": {
                    "regexp": "^(.*):(\\d+):(\\d+):\\s+(warning|error):\\s+(.*)$",
                    "file": 1,
                    "line": 2,
                    "column": 3,
                    "severity": 4,
                    "message": 5
                }
            }
        },
        {
            "label": "save_and_compile_for_C",
            "command": "gcc",
            "args": [
                "${file}",
                "-g",
                "-o",
                "${fileDirname}/${fileBasenameNoExtension}"
            ],
            "group": "build",
            "problemMatcher": {
                "fileLocation": ["relative", "${workspaceRoot}"],
                "pattern": {
                    "regexp": "^(.*):(\\d+):(\\d+):\\s+(warning|error):\\s+(.*)$",
                    "file": 1,
                    "line": 2,
                    "column": 3,
                    "severity": 4,
                    "message": 5
                }
            }
        },
        {
            "label": "execute",
            "command": "cmd",
            "group": "test",
            "args": [
                "/C", "${fileDirname}\\${fileBasenameNoExtension}"
            ]
        }
    ]
}

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[04] Task Breakdown

Task label	Compiler	Input files	Use case
save_and_compile_for_C++-groups	g++	All *.cpp in current dir	Multi-file C++ project
save_and_compile_for_C++-single	g++	Current file only	Single-file C++ sketch
save_and_compile_for_C	gcc	Current file only	Single-file C program
execute	cmd /C	Compiled binary	Run the output on Windows

Key argument — groups task:

"${fileDirname}/*${fileExtname}"

This glob expands at shell evaluation time to every file matching the extension of the open file inside its directory. If you have main.cpp open, VS Code sends /absolute/path/to/project/*.cpp to g++.

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[05] Running the Build Task

1. Open any .cpp file in the target directory.
2. Press Ctrl+Shift+B (or Cmd+Shift+B on macOS) to open the build task picker.
3. Select save_and_compile_for_C++-groups to compile all files in the directory.
4. Check the Terminal panel for compiler output and errors.

To set one task as the default build (Ctrl+Shift+B runs it directly without a picker), add "group": { "kind": "build", "isDefault": true } to that task’s group field.

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[06] Troubleshooting

Symptom	Likely cause	Fix
g++: command not found	g++ not on PATH	Install build-essential (Linux) or MinGW (Windows)
Glob not expanding	Shell does not support glob	Use "type": "shell" and wrap the arg in quotes
Only one file compiled	Wrong task selected	Pick the -groups task, not -single
Binary not found after compile	Output path mismatch	Check ${fileDirname}/${fileBasenameNoExtension} resolves correctly in the terminal

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[07] Reference

VS Code Variables Reference

VS Code Tasks documentation