Currently, yes. Once Go has a moving garbage collector (soon-ish), no. A moving garbage collector can move objects around. This would invalidate pointers in C,

Currently, yes. Once Go has a moving garbage collector (soon-ish), no. A moving garbage collector can move objects around. This would invalidate pointers in C, since the GC can run concurrently with C code (even if it didn't, it would invalidate pointers to object allocated in Go in C structs). To make things work, you have to allocate date used in C in C and pass Go variables only by value.