Global variables A global variable places greater demand on system resources - it needs to be retained in memory (RAM) throughout the entire execution of a program.

I read that by default, a Microsoft dll always gives each program a private copy of global variables. So that function not working would make sense, but I defined my variable in a shared data segment.

When the macro processor executes a macro program statement that can create a macro variable (such as a %LET statement), the macro processor attempts to change the value of an existing macro variable ...