MT4 Debugging

Fix MQL4 compiler errors by category, not guesswork.

The fastest MQL4 debugging starts by classifying the error: missing declaration, wrong type, missing brace, legacy function pattern, or bad function call.

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The developer wants quick explanations of common MT4 MetaEditor compiler messages.

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Declaration errors

Undeclared variables, missing extern inputs, and function names out of scope should be fixed before runtime issues.

Declare inputs at top level

Avoid duplicate names

Check function spelling

Type errors

MQL4 can be strict around string, int, double, and bool conversions. Normalize your types before adding more logic.

Cast intentionally

Normalize prices as double

Avoid comparing strings to numbers

Structure errors

Missing braces and semicolons can create misleading later errors. Reformat before rewriting the strategy.

Match braces

Close function blocks

Compile after structural fixes

Use the tool

Paste the MQL4 compiler output into Workfusion and get a full fixed draft, not only a small snippet.

Fix the first error first

Keep full EA context attached

Recompile before changing strategy logic

Open compiler fix desk Open related tool page

Related guides

Continue the EA build path.

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