The predefined Variables
For each executable mql5-program a set of predefined variables is supported, which reflect the state of the current price chart by the moment a mql5-program (Expert Advisor, script or custom indicator) is started.
Values of predefined variables are set by the client terminal before a mql5-program is started. Predefined variables are constant and cannot be changed from a mql5-program. As exception, there is a special variable _LastError, which can be reset to 0 by the ResetLastError function.
Variable |
Value |
|---|---|
The _AppliedTo variable allows finding out the type of data, used for indicator calculation |
|
Number of decimal places |
|
Size of the current symbol point in the quote currency |
|
The last error code |
|
Timeframe of the current chart |
|
Current status of the generator of pseudo-random integers |
|
Program stop flag |
|
Symbol name of the current chart |
|
Uninitialization reason code |
|
The _IsX64 variable allows finding out the bit version of the terminal, in which an MQL5 application is running |
Predefined variables cannot be defined in a library. A library uses such variables that are defined in program from which this library is called.