Thx Ian to pointing me to the documentation I read it, but still unsure regarding my example. Probably rule number 4 could apply, so let me go through my example and correct me if I'm wrong.
1. C.CreateApp() creates memory in C code and returns it as C void pointer 2. Go function CreateApp() returns that as MyAppHwnd (uintptr ) so MyAppHwnd contains a valid C memory address 3. app variable holds still a valid C memory address as long as it is not deleted in C code 4. So calling ShowApp() it should be legit to convert MyAppHwnd back to an unsafe.Pointer and cast it to C.MyAppPtr. It is still a valid memory address in C and therefore should be interpreted as pointer in C, right? So therefore the warning can be ignored or do I miss something important? Cheers Sandro Ian Lance Taylor schrieb am Freitag, 9. Juli 2021 um 05:37:16 UTC+2: > On Thu, Jul 8, 2021 at 10:09 AM snmed <sandro....@gmail.com> wrote: > > > > Thanks for your reply. I came across a similar solution today, I made a > struct which is visible outside the package and use a private field myApp > C.MyAppPtr to hide the C type. > > I still wondering why the uintptr version works but shows a warning > "possible misuse of unsafe.pointer", CGO documentation is not very clear to > me about the intricacies of type conversions between Go and C. > > There is a very limited number of cases in which it is OK to convert a > pointer to uintptr. Those cases are described at > https://golang.org/pkg/unsafe. > > Ian > -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/golang-nuts/72ea6248-f845-45c4-94b9-fab7027a60b2n%40googlegroups.com.
