# Use Syntax to drive Boolean in Level BluePrint

**URL:** <https://forums.unrealengine.com/t/use-syntax-to-drive-boolean-in-level-blueprint/312630>\
**Category:** Blueprint\
**Tags:** bool, syntax, unreal-engine, Blueprint, question\
**Created:** [March 26, 2015, 2:28am UTC](https://forums.unrealengine.com/t/use-syntax-to-drive-boolean-in-level-blueprint/312630 "2015-03-26T02:28:40Z")\
**Posts on this page:** 1\
**Showing post:** 3

<div class="post-metadata">

**Author:** ![mindfane](https://d1ap1mz92jnks1.cloudfront.net/user_avatar/forums.unrealengine.com/mindfane/32/710746_2.png) [@mindfane](https://forums.unrealengine.com/u/mindfane)\
**Post date:** [March 26, 2015, 3:58am UTC](https://forums.unrealengine.com/t/use-syntax-to-drive-boolean-in-level-blueprint/312630/3 "2015-03-26T03:58:20Z")

</div>

Assuming that you want to call FileExists or a similar C++ function from your Blueprint,

This is what you should do when you want to expose a built-in function which is not available in BP to blueprint:  
Create a new C++ class extended from UBlueprintFunctionLibrary. Declare a wrapper function that accepts the same parameters as the function you want to expose.  
So in this case:

```
UFUNCTION(BlueprintPure, Category="Wrapper")
public static bool MyFileExists(const FString & InPath)

```

Later you define this function something like this:

```
bool MyFileExists(const FString & InPath) {
  return FPaths::FileExists(InPath);
}

```

Now once you compile the code, your custom function MyFileExists will be available in all your blueprints (you might want to disable ‘ContextSensitive’).

This should be useful:

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