在Linux中的多个独立程序之间共享相同的变量

I want to share a variable between more than one independent C executables in Linux. That is, a program will write on an array and set a flag so that no other program can use it, and after this operation it'll unset the flag and then another program will read the array. I tried using the same custom header file (containing the variable) in every program, but it seems different instances of the variables are created when the programs are invoked.I want to share a variable between more than on