Do I have to free structs created with Cgo?

Question

I create C structs in my Go code, like this:

var data C.MyStruct_t

Do I have to free them manually at some point, like I do when I use CString? With CString I often do something like:

ctitle := C.String(title)
defer C.free(unsafe.Pointer(&ctitle))
C.my_func(&ctitle)

Answer 1

No. You only call free on something that was allocated via the C *alloc functions. The C.CString and C.CBytes functions are documented as doing so internally, and requiring the use of C.free.

In this case even though data is of type C.MyStruct_t it is allocated in Go, and therefor will be handled by the Go garbage collector.