How to Run C Code in NodeJS?

Developers can take advantage of Node.js's robust ecosystem and performance by running C code within the framework. Child processes, Node.js extensions, and the Foreign Function Interface (FFI) can all assist in this. There is flexibility to integrate C code based on particular requirements, as each solution has its own advantages, disadvantages, and use cases.

These are the following approaches to run C code in nodeJs:

By using Native Addons

To connect JavaScript and C/C++ code, Node.js offers a feature called "Native Addons.". This approach involves writing C/C++ code and compiling it into a shared library, which is then loaded into Node.js using require().

Syntax:

const addon = require('./addon');
console.log(addon.method());

Example: This example shows the execution of C file using nodejs.

#include <node.h>

namespace demo {
    using v8::FunctionCallbackInfo;
    using v8::Isolate;
    using v8::Local;
    using v8::Object;
    using v8::String;
    using v8::Value;

    void Method(const FunctionCallbackInfo<Value>& args) {
        Isolate* isolate = args.GetIsolate();
        args.GetReturnValue().Set(String::NewFromUtf8(isolate, "Hello from GFG"));
    }

    void Initialize(Local<Object> exports) {
        NODE_SET_METHOD(exports, "method", Method);
    }

    NODE_MODULE(NODE_GYP_MODULE_NAME, Initialize)
}

const addon = require('./build/Release/addon');
console.log(addon.method()); 

Steps to run:

Step 1: Create a file called addon.cc and copy the C code into it.

Step 2: Create a file called binding.gyp in the same directory with the following content:

{
  "targets": [
    {
      "target_name": "addon",
      "sources": [ "addon.cc" ]
    }
  ]
}

Step 3: Open a terminal, navigate to the directory containing addon.cc and binding.gyp, and run the following commands to build the addon:

node-gyp configure
node-gyp build

Step 4: Create a file called app.js and copy the JavaScript code into it.

Step 5: Run the Node.js application with the following command:

node app.js

Output:

By using Child Processes

Node.js offers the child_process module, allowing execution of external processes. This approach involves spawning a child process to run a compiled C program and communicating with it via standard streams

Syntax:

const { exec } = require('child_process');
exec('./my_c_program', (err, stdout, stderr) => {
  if (err) {
    console.error(err);
    return;
  }
  console.log(stdout);
});

Example: This example shows the execution of C file using nodejs.

#include <stdio.h>

int main() {
    printf("Hello from C\n");
    return 0;
}

const { exec } = require('child_process');
exec('./my_c_program', (err, stdout, stderr) => {
  if (err) {
    console.error(err);
    return;
  }
  console.log(stdout); // Output: Hello from C
});

Steps to run:

Step 1: Create a file called my_c_program.c and copy the C code into it.

Step 2: Compile the C code with the following command:

gcc -o my_c_program my_c_program.c

Step 3: Create a file called app.js and copy the JavaScript code into it.

Step 4: Run the Node.js application with the following command:

node app.js

Output:

By executing shell commands

Another approach is to execute C code as if it were a shell command. This method utilizes Node.js's `child_process` module to run the C compiler (`gcc`) and execute the compiled binary.

Syntax:

const { exec } = require('child_process');
exec('gcc -o my_c_program my_c_program.c && ./my_c_program', (err, stdout, stderr) => {
  if (err) {
    console.error(err);
    return;
  }
  console.log(stdout);
});

Example: This example shows the execution of C file using nodejs.

#include <stdio.h>

int main() {
    printf("Hello from C\n");
    return 0;
}

const { exec } = require('child_process');
exec('gcc -o my_c_program my_c_program.c &&
    ./my_c_program', (err, stdout, stderr) => {
  if (err) {
    console.error(err);
    return;
  }
  console.log(stdout);
});

Steps to run:

Step 1: Create a file called my_c_program.c and copy the C code into it.

Step 2: Create a file called app.js and copy the JavaScript code into it.

Step 3: Run the Node.js application with the following command:

node app.js

Output: