Hi, There is something that puzzles me a lot in the doc about cgo.Handle there https://pkg.go.dev/runtime/cgo. It says:
*Some C functions accept a void* argument that points to an arbitrary data value supplied by the caller. It is not safe to coerce a cgo.Handle (an integer) to a Go unsafe.Pointer, but instead we can pass the address of the cgo.Handle to the void* parameter, as in this variant of the previous example: * I was under the impression that casting a uintptr to an unsafe.Pointer just to call a C function (that accepts a void*) is somewhat valid. (This is not clearly specified as a valid case in the doc of unsafe.Pointer, so, it might be invalid from a very pedantic point of view). The advice given in the doc looks worst. Taking the address of a local variable and giving it to C looks even more undefined (if C stores the pointer and reuse it after the original call returns). Don't we have a doc issue there ? I know that in C, the conversion uintptr -> void* is subject to debate (trap representation, ...). In practice, nobody cares because *It just works*. (example of the nobody cares https://www.freedesktop.org/software/gstreamer-sdk/data/docs/latest/glib/glib-Type-Conversion-Macros.html) In practice, I'm almost certain that the naïve code that just gives the cgo.Handle to a C function as a void* is *much* safer that the pattern suggested in the doc. So should the doc be changed, or am I missing some important piece ? Thanks Fred -- 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/49cadd8f-89b4-4f91-8ad3-241768758dc3n%40googlegroups.com.
