1.以32bit编译（gcc -m32）
sizeof char =1
sizeof short =2
sizeof int =4
sizeof long =4
sizeof long long=8
sizeof float =4
sizeof double =8
sizeof void =1
sizeof enum type =4
sizeof void * =4
sizeof int =4
sizeof char =4
2.以64bit编译（gcc -m64）
sizeof char =1
sizeof short =2
sizeof int =4
sizeof long =8
sizeof long long=8
sizeof float =4
sizeof double =8
sizeof void =1
sizeof enum type =4
sizeof void * =8
sizeof int =8
sizeof char =8