how to understand this define macro?
android, c
Solution
`&&` is the label value operator. It returns he addres of a label defined in the current scope, used as operand. It is a `gcc` extension.
Problem
I am learning Dalvik VM code but stopped by some strange C define macros in file InterpC-portable.cpp. They're hard to understand for me. The code is: ``` # define H(_op) &&op_##_op ``` and in file libdex/DexOpcodes.h, it is used like this: ``` #define DEFINE_GOTO_TABLE(_name) \ static const void* _name[kNumPackedOpcodes] = { \ /* BEGIN(libdex-goto-table); GENERATED AUTOMATICALLY BY opcode-gen */ \ H(OP_NOP), \ H(OP_MOVE), \ H(OP_MOVE_FROM16), \ ... ``` OP_NOP, OP_MOVE, OP_MOVE_FROM16 are some enum variable. But what's the meaning of && operation in H(_op) macro? It doesn't make sense to get a pointer of pointer which doesn't store at memory. Anyone can help me? Thanks.