Shmem
A Shmem Demo
用gcc编译：(compile with gcc)
gcc -o writeShm writeShm.c common.c
gcc -o readShm readShm.c common.c
开启两个终端1和2（open two terminal）
1：运行writeShm(run writeShm)
./writeShm
2: 运行readShm(run readShm)
./readShm
在终端1输入任意字符:(type any string in terminal,as:)
hello
how are you
观察终端2的显示:(watch output in terminal 2:)
hello
how are you