Named Constants

All constants used in MQL4 can be divided into the following groups:

• Predefined macro substitutions — values are substituted during compilation;
• Mathematical constants — values of some mathematical expressions;
• Numerical type constants —  some of the simple type restrictions;
• Uninitialization reason codes — description of uninitialization reasons;
• Checking Object Pointer — enumeration of types of pointers returned by the CheckPointer() function;
• Other constants — all other constants.