MQL4 Reference Global Variables of the Terminal
Global Variables of the Client Terminal
There is a group set of functions for working with global variables.
Global variables of the client terminal should not be mixed up with variables declared in the global scope of the mql4 program.
Global variables are kept in the client terminal for 4 weeks since the last access, then they will be deleted automatically. An access to a global variable is not only setting of a new value, but reading of the global variable value, as well.
Global variables of the client terminal are accessible simultaneously from all mql4 programs launched in the client terminal.
When testing and optimizing the Expert Advisors that use global variables, keep in mind that client terminal and the Strategy Tester share common global variables. Therefore, the names of the global variables must be different from the names of the global variables used by other mql4 programs. Otherwise, it may lead to incorrect work of mql4 programs and inaccurate testing results.