~/Running C Code in Golang

Feb 15, 2025

Golang can run C code using the cgo tool. This enables calling C functions directly from Go, useful for performance or reusing legacy code.

First, add a special comment to your Go file to include C code:

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/*
#include <stdio.h>
#include <stdlib.h>
void hello() {
    printf("Hello from C\n");
}
*/
import "C"

func main() {
    C.hello()
}

• Use import "C" after the C code comment.
• You can call C functions as C.functionName().
• Use go run or go build as usual.
• Your system must have a C compiler installed.

To pass values between Go and C, use these types:

• C.int, C.double, etc map to C types.
• Use C.CString(goString) for passing Go strings to C.

For more complex use, see the cgo documentation. For cross compiling, check the FAQ.

Read more on calling C code from Go.