int _IsX64

The _IsX64 variable allows finding out the bit version of the terminal, in which an MQL5 application is running: _IsX64=0 for the 32-bit terminal and _IsX64!=0 for the 64-bit terminal.

Also, function TerminalInfoInteger(TERMINAL_X64) can be used.

Example:

// Checking the terminal, in which the program is running
   Print("_IsX64=",_IsX64);
   if(_IsX64)
      Print("Program ",__FILE__," is running in the 64-bit terminal");
   else
      Print("Program ",__FILE__," is running in the 32-bit terminal");
   Print("TerminalInfoInteger(TERMINAL_X64)=",TerminalInfoInteger(TERMINAL_X64));