cgo透传字节流 c语言调用go语言

直接上代码：

b := buf.Bytes()
rc := C.the_function(unsafe.Pointer(&b[0]), C.int(buf.Len()))


p := C.malloc(C.size_t(len(b)))
defer C.free(p)

// copy the data into the buffer, by converting it to a Go array
cBuf := (*[1 << 30]byte)(p)
copy(cBuf[:], b)
rc = C.the_function(p, C.int(buf.Len()))