It is still useless for me if you have struct with 'packed' attribute ie: http://lxr.free-electrons.com/source/fs/btrfs/ctree.h#L220 http://lxr.free-electrons.c

It is still useless for me if you have struct with 'packed' attribute ie: http://lxr.free-electrons.com/source/fs/btrfs/ctree.h#L220 http://lxr.free-electrons.com/source/fs/btrfs/ctree.h#L220 // +build ignore package tmp /* #include <btrfs/ctree.h> */ import "C" // 220 struct btrfs_disk_key { // 221 __le64 objectid; // 222 u8 type; // 223 __le64 offset; // 224 } __attribute__ ((__packed__)); type BtrfsDiskKey C.struct_btrfs_disk_key Output: $ go tool cgo -godefs test.go // Created by cgo -godefs - DO NOT EDIT // cgo -godefs test.go package tmp type BtrfsDiskKey struct { Objectid uint64 Type uint8 Pad_cgo_0 [8]byte } After all the experiments I created my own helper[1], which helps map C structure(even packed) to Go structure using reflect package. [1] https://github.com/plar/btrfs/blob/master/ioctl/mappings.go https://github.com/plar/btrfs/blob/master/ioctl/mappings.go