MQL4 ERR_ZERO_DIVIDE
MQL4 zero divide 4013 maps to ERR_ZERO_DIVIDE: zero divide. A calculation attempted to divide by zero, often after an empty sample, unchanged price range, or uninitialized value. Capture GetLastError immediately after the failed call, correct the cause, and retry only when the condition can change.
Open the Coding Agent, then choose MQL4 from the language menu.
#property strict
#property script_show_inputs
input double Numerator = 10.0;
input double Denominator = 0.0;
void OnStart()
{
if(Denominator == 0.0)
{
Print("Calculation stopped: denominator is zero.");
return;
}
double result = Numerator / Denominator;
if(!MathIsValidNumber(result))
{
Print("Calculation produced an invalid number.");
return;
}
Print("Result: ", DoubleToString(result, 6));
}The official MQL4 runtime table names error 4013 ERR_ZERO_DIVIDE and defines it as “zero divide.” A calculation attempted to divide by zero, often after an empty sample, unchanged price range, or uninitialized value.
The error number is evidence about one failed call, not a diagnosis of the whole EA. Read the API sentinel first, then call GetLastError immediately because that function returns the current _LastError value and resets it.
Start with the inputs and external state that existed at the failure point. A later log entry or a successful call can overwrite the useful context.
Do not retry the same calculation. Correct the data or branch for the zero case, then rerun the calculation with a defined result.
Keep the original trading and risk rules intact. A workaround that widens stops, increases volume, changes an account setting, or ignores a failed return value can hide the symptom while changing the system.
| Check | Action |
|---|---|
| A denominator input is zero or was never initialized | Check the denominator before every division and define the zero case explicitly. |
| A range such as high minus low equals zero | Skip or substitute only when the strategy specification defines that behavior. |
| A count remains zero because no bars or orders matched | Check the matched count before calculating an average. |
| An invalid numeric result flows into a later calculation | Use MathIsValidNumber after calculations that can produce invalid values. |
The script rejects a zero denominator before division and checks that the result is a valid number. The correct fallback depends on the indicator or strategy rule.
The example improves validation and logging. It does not prove the operation will be accepted by a broker or behave safely in live trading.
#property strict
#property script_show_inputs
input double Numerator = 10.0;
input double Denominator = 0.0;
void OnStart()
{
if(Denominator == 0.0)
{
Print("Calculation stopped: denominator is zero.");
return;
}
double result = Numerator / Denominator;
if(!MathIsValidNumber(result))
{
Print("Calculation produced an invalid number.");
return;
}
Print("Result: ", DoubleToString(result, 6));
}Pineify can generate or revise one self-contained .mq4 file with MQL4-specific reference context. Its independent static checker returns MetaEditor diagnostics so you can repair source issues before testing in your own MT4 environment.
Open MQL4 Coding AgentStatic diagnostics do not prove runtime behavior, backtest results, broker compatibility, or live-trading safety.
Check the API return value before interpreting an error number from the log.
Call GetLastError immediately and record error 4013, symbol, prices, volume, ticket, and terminal state relevant to the operation.
Check the denominator before every division and define the zero case explicitly.
Compile the revised source, then test with the same MT4 build, broker, symbol, account permissions, and market state.
ERR_ZERO_DIVIDE means zero divide. The code should still identify which API returned failure and log the inputs used for that call.
A denominator input is zero or was never initialized A range such as high minus low equals zero A count remains zero because no bars or orders matched An invalid numeric result flows into a later calculation
Do not retry the same calculation. Correct the data or branch for the zero case, then rerun the calculation with a defined result.
It reports the current _LastError value and resets it. Other operations can change the error state, so a delayed read may describe the wrong call.
Pineify can revise a self-contained .mq4 file, add validation and error logging, and return static MetaEditor diagnostics. It cannot prove broker acceptance, account permissions, market availability, or live execution.
Last verified against the linked official references on . Compile and test the final source in the MetaTrader 4 build, broker, symbol, and account environment you plan to use.
Define the requirement, inspect the generated source, repair diagnostics, and test the behavior in your own MT4 environment.
Open Coding Agent