Function Unpack

contrib/stacktrace/stacktrace.amalgamation.cpp:2192–2196

Unpack x into a pid and two file descriptors, where x was created with Pack().

// Unpack x into a pid and two file descriptors, where x was created with
// Pack().
static void Unpack(uint64_t x, int* pid, int* read_fd, int* write_fd) {
	*pid = x >> 48;
	*read_fd = (x >> 24) & 0xffffff;
	*write_fd = x & 0xffffff;
}

// Return whether the byte at *addr is readable, without faulting.
// Save and restores errno.   Returns true on systems where