cgotest.go

package main
// cgo test function
//  build this:
//   1.  go build -o cgotest1 cgotest.go
//   2.  go build -o cgotest2 -ldflags='-linkmode=internal' cgotest.go

/*
#include <stdio.h>

__attribute__((constructor)) void cgofunc() {
        printf("Run CGO function! \n");
}
*/
import "C"

import "time"

func main() {
        time.Sleep(10*time.Second)
}

When linkmode is internal, C constructor is not executed...
$ ./cgotest1
Run CGO function!
$ ./cgotest2
$
Then, cgotest1 has the symbol 'cgofunc', but cgotest2 has none.
$ nm cgotest1 | grep cgofunc
0000000000436ca0 T cgofunc
$ nm cgotest2 | grep cgofunc
$