MT5 · Compilation errors
MT5 110 · Symbol unknown to compiler | YI GOLD
Official meaning
Symbol unknown to compiler
Possible causes · YI GOLD suggestions
Determine the cause from the official meaning, the triggering function and terminal logs.
Troubleshooting · YI GOLD suggestions
Locate the first reported line in MetaEditor. Check syntax, types, function signatures, includes and file permissions, then recompile.