Sets the string type property value for a custom symbol.
[in] Custom symbol name.
[in] Symbol property ID. The value can be one of the values of the ENUM_SYMBOL_INFO_STRING enumeration.
[in] A string type variable containing the property value.
true – success, otherwise – false. To get information about the error, call the GetLastError() function.
The minute and tick history of the custom symbol is completely removed if the SYMBOL_FORMULA property (setting the equation for the custom symbol price construction) is changed in the symbol specification. After deleting the custom symbol history, the terminal attempts to create a new history using the new equation. The same happens when the custom symbol equation is changed manually.