On Mon, Dec 9, 2019 at 8:57 AM <p...@cpan.org> wrote: > > I would like to ask some technical question about cgo and long jumps. > > In Go I have written shared library which exports C API and therefore > can be called by other C applications. This my library is compiling with > cgo, more precisely via: go build -buildmode=c-shared -compiler gc > > Now I would like to call from my Go library some C function which may > call longjmp(). And setjmp() was already called by application which is > using my Go library. > > It is possible to call from Go C function which calls longjmp() which > jumps outside of that my Go library? What would happen with Go garbage > collector and "defer" code? > > To imagine, whole stack looks like this: > > +------------------------------------------+ > | C application | > | main(): | > | call setjmp() | > | call f1() from Go library | > | ... | > +------------------------------------------+ > | Go library with exported C f1() function | > | f1(): | > | do something in Go | > | call f2() from C library | > | ... | > | return from f1() | > +------------------------------------------+ > | C library with exported f2() function | > | f2(): | > | do something in C | > | if error call longjmp() | > | else return from f2() | > +------------------------------------------+ > > And if longjmp() is called then it jumps to main() where setjmp() was > called. So effectively f1() function (in Go) does not return.
I'm pretty sure that won't work at all. Sorry. Certainly no Go deferred functions will be run. I don't think this would break the garbage collector as such, but I expect that it would break the Go scheduler. In the best case you'll be left with a dangling goroutine that will never be run and never go away. 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/CAOyqgcXuHZWAkvWWu5DKR1aMAGQG26PRBvQz7UpSEsN81huq%2Bw%40mail.gmail.com.
