What It Means & How to Fix It

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🧠 Why You’re Seeing This Error

The C4244 warning (or error if your compiler treats warnings as errors) means you’re converting a larger type into a smaller one, and the compiler is warning you that data might get lost in the process.

In UE5, this often happens when:

• You assign a double or float to an int32 or uint8
• You assign a 64-bit integer to a 32-bit one
• You’re using numeric literals or math that result in a wider type than the variable you’re assigning to

C++ is warning you that the value might be truncated or lose precision.

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💥 Example Error Message

warning C4244: 'initializing': conversion from 'double' to 'float', possible loss of data

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🛠️ Example Code

double PreciseValue = 3.14159;
float Radius = PreciseValue; // ⚠️ C4244: double to float conversion

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✅ How to Fix C4244 in UE5 – Step-by-Step

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✔️ 1. Use an Explicit Cast to Acknowledge the Conversion

If the conversion is safe and intentional, you can cast it directly to suppress the warning.

Fix:

float Radius = static_cast(PreciseValue); // ✅ Intent is now clear

This tells the compiler “I know what I’m doing” and silences the warning.

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✔️ 2. Use the Same Type When Possible

Avoid converting between mismatched types in the first place.

Fix:

float PreciseValue = 3.14159f; // ✅ Use float literal
float Radius = PreciseValue;

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✔️ 3. Handle Integer Conversions Safely

Wrong:

int32 Small = 255;
uint8 Byte = Small; // ⚠️ Possible data loss if Small > 255

Fix:

uint8 Byte = static_cast(Small); // ✅ Explicit cast

You can also check the range manually if needed.

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✔️ 4. Turn Warnings into Errors Only When Ready

If you’re using -Werror or Treat Warnings As Errors in Visual Studio, this will block compilation. You can either:

• Fix all warnings
• Downgrade this specific warning
• Temporarily disable it with #pragma warning(disable: 4244) (not recommended long-term)

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✅ Summary: How to Fix C4244 in UE5

Cause	Fix Example
Float-to-int or double-to-float	Use static_cast<Type>()
Integer truncation	Cast or clamp manually
Mismatched numeric literals	Use suffixes like 3.0f for float
Compiler treating warnings as errors	Fix, cast, or temporarily disable the warning