[swift-users] question about swift and c callbacks

Yang Yang cometyang at gmail.com
Thu Jan 5 10:29:32 CST 2017


sorry´╝î i made mistake on compiling. It still report the same link error.

Yang
On Wed, Jan 4, 2017 at 11:20 PM Yang Yang <cometyang at gmail.com> wrote:

> Thanks.
> It compiled successfully now under linux.
>
>
> 2017-01-04 12:29 GMT-06:00 Joe Groff <jgroff at apple.com>:
>
>
>
>
> > On Dec 30, 2016, at 11:17 AM, Yang Yang via swift-users <
> swift-users at swift.org> wrote:
>
>
> >
>
>
> > I try to wrap a c library in swift package named Test.
>
>
> > The code looks like this:
>
>
> >
>
>
> > Test1.h
>
>
> >
>
>
> > struct MyParams {
>
>
> >       int (*func)();
>
>
> > };
>
>
> >
>
>
> > typedef struct MyParams MyParams;
>
>
> >
>
>
> > Test2.h
>
>
> > #include "Test1.h"
>
>
> >
>
>
> > static int test(){
>
>
> >   return 0;
>
>
> > }
>
>
> >
>
>
> > void myTest()
>
>
> > {
>
>
> >       MyParams params;
>
>
> >       params.func = test;
>
>
> > }
>
>
> >
>
>
> >
>
>
> > Then I try to import the package into swift code and use
>
>
> > in Test.swift.
>
>
> > ************************
>
>
> > import Test
>
>
> >
>
>
> > class TestSwift {
>
>
> >   func runtest(){
>
>
> >     myTest()
>
>
> >   }
>
>
> > }
>
>
> >
>
>
> > However, the compiler report link error:
>
>
> > function myTest: error: undefined reference to 'test'
>
>
> >
>
>
> > If I comment out
>
>
> > "params.func = test;" in myTest.
>
>
> >
>
>
> > It successfully build. How should I handle this situation?
>
>
>
>
>
> Try making `test` static inline instead of just static.
>
>
>
>
>
> -Joe
>
>
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>
>
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