In the link for imigtration from MQL4 to MQL5, it says to use the following variable TFMigrate.
My complier says: This is an undeclar variable. What is it....?
Can somebody help..?
If you mean the article Migrating from MQL4 to MQL5 , TFMigrate is not a variable, it's the function for convesion of MT4 time periods, suggested by author of the article.
If you needed it, you can find its code at the beginning of the article.