On Tue, Oct 1, 2019 at 7:36 PM <dr.ch.mau...@gmail.com> wrote:
>
> what is wrong with the following simple code, which yields "undefined
> reference for F" ?
>
>
> file f.go:
>
> package main
> // #include "f.h"
> // void f (int a) { F(a) }
> import "C"
>
> func F(a int) { println(a) }
> func main() { C.f(7) }
>
>
> file f.h:
>
> extern void F (int a);
>
> //export F
Putting "//export F" in f.h isn't going to do anything. A "//export"
comment has to appear just before the Go function that you want to
export.
Note that as explained at https://golang.org/cmd/cgo, "Using //export
in a file places a restriction on the preamble: since it is copied
into two different C output files, it must not contain any
definitions, only declarations." In the above f.go, "void f (int a) {
F(a) }" is a definition. So you can't use that in conjunction with an
"//export" comment.
Ian
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