Calling C Function From Go
suggest changeCgo enables the creation of Go packages that call C code. To use cgo
write normal Go code that imports a pseudo-package “C”. The Go code can then refer to types such as C.int
, or functions such as C.Add
. The import of “C” is immediately preceded by a comment, that comment, called the preamble, is used as a header when compiling the C parts of the package. Note that there must be no blank lines in between the cgo
comment and the import statement. Note that import "C"
can not grouped with other imports into a parenthesized, “factored” import statement. You must write multiple import statements, like:
import "C"
import "fmt"
And it is good style to use the factored import statement, for other imports, like:
import "C"
import (
"fmt"
"math"
)
Simple example using cgo
:
package main
//int Add(int a, int b){
// return a+b;
//}
import "C"
import "fmt"
func main() {
a := C.int(10)
b := C.int(20)
c := C.Add(a, b)
fmt.Println(c) // 30
}
Then go build
, and run it, output:
30
To build cgo
packages, just use go build
or go install
as usual. The go tool
recognizes the special "C"
import and automatically uses cgo
for those files.