UDocumentation UE5.7 10.02.2026 (Source)
API documentation for Unreal Engine 5.7
Classes | Namespaces | Macros | Functions | Variables
AssertionMacros.h File Reference
#include "CoreTypes.h"
#include "HAL/Platform.h"
#include "HAL/PlatformMisc.h"
#include "HAL/PreprocessorHelpers.h"
#include "Misc/VarArgs.h"
#include "String/FormatStringSan.h"
#include "Templates/EnableIf.h"
#include "Templates/IsArrayOrRefOfTypeByPredicate.h"
#include "Templates/IsValidVariadicFunctionArg.h"
#include "Traits/IsCharEncodingCompatibleWith.h"
#include <atomic>

Go to the source code of this file.

Classes

struct  FEnsureHandlerArgs
 
struct  FDebug
 

Namespaces

namespace  ELogVerbosity
 
namespace  UEAsserts_Private
 
namespace  UE
 
namespace  UE::Assert
 
namespace  UE::Assert::Private
 

Macros

#define UE_DEBUG_SECTION
 
#define UE_DEBUG_BREAK_AND_PROMPT_FOR_REMOTE()    if (!FPlatformMisc::IsDebuggerPresent()) { FPlatformMisc::PromptForRemoteDebugging(false); } UE_DEBUG_BREAK();
 
#define _DebugBreakAndPromptForRemote()    UE_DEPRECATED_MACRO(5.1, "Use UE_DEBUG_BREAK_AND_PROMPT_FOR_REMOTE.")
 
#define PLATFORM_BREAK_IF_DESIRED()   if (LIKELY(!GIgnoreDebugger)) { PLATFORM_BREAK(); }
 
#define checkCode(...)
 
#define check(expr)   { CA_ASSUME(expr); }
 
#define checkf(expr, format, ...)   { CA_ASSUME(expr); }
 
#define checkNoEntry()
 
#define checkNoReentry()
 
#define checkNoRecursion()
 
#define verify(expr)   { if(UNLIKELY(!(expr))){ CA_ASSUME(false); } }
 
#define verifyf(expr, format, ...)   { if(UNLIKELY(!(expr))){ CA_ASSUME(false); } }
 
#define unimplemented()   { CA_ASSUME(false); }
 
#define checkSlow(expr)   { CA_ASSUME(expr); }
 
#define checkfSlow(expr, format, ...)   { CA_ASSUME(expr); }
 
#define verifySlow(expr)   { if(UNLIKELY(!(expr))) { CA_ASSUME(false); } }
 
#define ensure( InExpression)   (LIKELY(!!(InExpression)))
 
#define ensureMsgf( InExpression, InFormat, ...)   (LIKELY(!!(InExpression)))
 
#define ensureAlways( InExpression)   (LIKELY(!!(InExpression)))
 
#define ensureAlwaysMsgf(InExpression, InFormat, ...)   (LIKELY(!!(InExpression)))
 
#define GET_ENUMERATOR_NAME_CHECKED(EnumName, EnumeratorName)    (FName(GET_ENUMERATOR_NAME_STRING_VIEW_CHECKED(EnumName, EnumeratorName)))
 
#define GET_ENUMERATOR_NAME_STRING_CHECKED(EnumName, EnumeratorName)    ((void)sizeof(UEAsserts_Private::GetMemberNameCheckedJunk(EnumName::EnumeratorName)), TEXT(#EnumeratorName))
 
#define GET_ENUMERATOR_NAME_STRING_VIEW_CHECKED(EnumName, EnumeratorName)    ((void)sizeof(UEAsserts_Private::GetMemberNameCheckedJunk(EnumName::EnumeratorName)), TEXTVIEW(#EnumeratorName))
 
#define GET_MEMBER_NAME_CHECKED(ClassName, MemberName)    (FName(GET_MEMBER_NAME_STRING_VIEW_CHECKED(ClassName, MemberName)))
 
#define GET_MEMBER_NAME_STRING_CHECKED(ClassName, MemberName)    ((void)sizeof(UEAsserts_Private::GetMemberNameCheckedJunk(((ClassName*)0)->MemberName)), TEXT(#MemberName))
 
#define GET_MEMBER_NAME_STRING_VIEW_CHECKED(ClassName, MemberName)    ((void)sizeof(UEAsserts_Private::GetMemberNameCheckedJunk(((ClassName*)0)->MemberName)), TEXTVIEW(#MemberName))
 
#define GET_FUNCTION_NAME_CHECKED(ClassName, FunctionName)    (FName(GET_FUNCTION_NAME_STRING_VIEW_CHECKED(ClassName, FunctionName)))
 
#define GET_FUNCTION_NAME_STRING_CHECKED(ClassName, FunctionName)    ((void)sizeof(&ClassName::FunctionName), TEXT(#FunctionName))
 
#define GET_FUNCTION_NAME_STRING_VIEW_CHECKED(ClassName, FunctionName)    ((void)sizeof(&ClassName::FunctionName), TEXTVIEW(#FunctionName))
 
#define GET_FUNCTION_NAME_CHECKED_OneParam(ClassName, FunctionName, ArgType)    (FName(GET_FUNCTION_NAME_STRING_CHECKED_OneParam(ClassName, FunctionName, ArgType)))
 
#define GET_FUNCTION_NAME_CHECKED_TwoParams(ClassName, FunctionName, ArgType1, ArgType2)    (FName(GET_FUNCTION_NAME_STRING_CHECKED_TwoParams(ClassName, FunctionName, ArgType1, ArgType2)))
 
#define GET_FUNCTION_NAME_CHECKED_ThreeParams(ClassName, FunctionName, ArgType1, ArgType2, ArgType3)    (FName(GET_FUNCTION_NAME_STRING_CHECKED_ThreeParams(ClassName, FunctionName, ArgType1, ArgType2, ArgType3)))
 
#define GET_FUNCTION_NAME_CHECKED_FourParams(ClassName, FunctionName, ArgType1, ArgType2, ArgType3, ArgType4)    (FName(GET_FUNCTION_NAME_STRING_CHECKED_FourParams(ClassName, FunctionName, ArgType1, ArgType2, ArgType3, ArgType4)))
 
#define GET_FUNCTION_NAME_STRING_CHECKED_OneParam(ClassName, FunctionName, ArgType)    ((void)sizeof((std::declval<ClassName&>().FunctionName(std::declval<PREPROCESSOR_REMOVE_OPTIONAL_PARENS(ArgType)>()), (int)0)), TEXT(#FunctionName))
 
#define GET_FUNCTION_NAME_STRING_CHECKED_TwoParams(ClassName, FunctionName, ArgType1, ArgType2)    ((void)sizeof((std::declval<ClassName&>().FunctionName(std::declval<PREPROCESSOR_REMOVE_OPTIONAL_PARENS(ArgType1)>(), std::declval<PREPROCESSOR_REMOVE_OPTIONAL_PARENS(ArgType2)>()), (int)0)), TEXT(#FunctionName))
 
#define GET_FUNCTION_NAME_STRING_CHECKED_ThreeParams(ClassName, FunctionName, ArgType1, ArgType2, ArgType3)    ((void)sizeof((std::declval<ClassName&>().FunctionName(std::declval<PREPROCESSOR_REMOVE_OPTIONAL_PARENS(ArgType1)>(), std::declval<PREPROCESSOR_REMOVE_OPTIONAL_PARENS(ArgType2)>(), std::declval<PREPROCESSOR_REMOVE_OPTIONAL_PARENS(ArgType3)>()), (int)0)), TEXT(#FunctionName))
 
#define GET_FUNCTION_NAME_STRING_CHECKED_FourParams(ClassName, FunctionName, ArgType1, ArgType2, ArgType3, ArgType4)    ((void)sizeof((std::declval<ClassName&>().FunctionName(std::declval<PREPROCESSOR_REMOVE_OPTIONAL_PARENS(ArgType1)>(), std::declval<PREPROCESSOR_REMOVE_OPTIONAL_PARENS(ArgType2)>(), std::declval<PREPROCESSOR_REMOVE_OPTIONAL_PARENS(ArgType3)>(), std::declval<PREPROCESSOR_REMOVE_OPTIONAL_PARENS(ArgType4)>()), (int)0)), TEXT(#FunctionName))
 
#define LowLevelFatalError(Format, ...)
 

Functions

CORE_API void PrintScriptCallstack ()
 
CORE_API TFunction< bool(const FEnsureHandlerArgs &Args)> SetEnsureHandler (TFunction< bool(const FEnsureHandlerArgs &Args)> EnsureHandler)
 
CORE_API TFunction< bool(const FEnsureHandlerArgs &Args)> GetEnsureHandler ()
 
template<typename RetType = void, class InnerType , typename... ArgTypes>
RetType UE_COLD UE_DEBUG_SECTION DispatchCheckVerify (InnerType &&Inner, ArgTypes const &... Args)
 
template<typename T >
bool UEAsserts_Private::GetMemberNameCheckedJunk (const T &)
 
template<typename T >
bool UEAsserts_Private::GetMemberNameCheckedJunk (const volatile T &)
 
template<typename R , typename ... Args>
bool UEAsserts_Private::GetMemberNameCheckedJunk (R(*)(Args...))
 
CORE_API void UE_COLD UE_DEBUG_SECTION VARARGS UE::Assert::Private::ProcessLowLevelFatalError (const ANSICHAR *File, int32 Line, const TCHAR *Format,...)
 
template<typename... ArgTypes>
UE_REWRITE void LowLevelFatalErrorHandler (const ANSICHAR *File, int32 Line, const TCHAR *Format=TEXT(""), ArgTypes... Args)
 

Variables

CORE_API bool GIgnoreDebugger
 

Macro Definition Documentation

◆ _DebugBreakAndPromptForRemote

#define _DebugBreakAndPromptForRemote ( )     UE_DEPRECATED_MACRO(5.1, "Use UE_DEBUG_BREAK_AND_PROMPT_FOR_REMOTE.")

◆ check

#define check (   expr)    { CA_ASSUME(expr); }

◆ checkCode

#define checkCode (   ...)

◆ checkf

#define checkf (   expr,
  format,
  ... 
)    { CA_ASSUME(expr); }

◆ checkfSlow

#define checkfSlow (   expr,
  format,
  ... 
)    { CA_ASSUME(expr); }

◆ checkNoEntry

#define checkNoEntry ( )

◆ checkNoRecursion

#define checkNoRecursion ( )

◆ checkNoReentry

#define checkNoReentry ( )

◆ checkSlow

#define checkSlow (   expr)    { CA_ASSUME(expr); }

◆ ensure

#define ensure (   InExpression)    (LIKELY(!!(InExpression)))

ensure() can be used to test for non-fatal errors at runtime

Rather than crashing, an error report (with a full call stack) will be logged and submitted to the crash server. This is useful when you want runtime code verification but you're handling the error case anyway.

Note: ensure() can be nested within conditionals!

Example: 

if (ensure(InObject != nullptr))
{
    InObject->Modify();
}

This code is safe to execute as the pointer dereference is wrapped in a non-nullptr conditional block, but you still want to find out if this ever happens so you can avoid side effects. Using ensure() here will force a crash report to be generated without crashing the application (and potentially causing editor users to lose unsaved work.)

ensure() resolves to just evaluate the expression when DO_CHECK is 0 (typically shipping or test builds).

By default a given call site will only print the callstack and submit the 'crash report' the first time an ensure is hit in a session; ensureAlways can be used instead if you want to handle every failure

◆ ensureAlways

#define ensureAlways (   InExpression)    (LIKELY(!!(InExpression)))

◆ ensureAlwaysMsgf

#define ensureAlwaysMsgf (   InExpression,
  InFormat,
  ... 
)    (LIKELY(!!(InExpression)))

◆ ensureMsgf

#define ensureMsgf (   InExpression,
  InFormat,
  ... 
)    (LIKELY(!!(InExpression)))

◆ GET_ENUMERATOR_NAME_CHECKED

#define GET_ENUMERATOR_NAME_CHECKED (   EnumName,
  EnumeratorName 
)     (FName(GET_ENUMERATOR_NAME_STRING_VIEW_CHECKED(EnumName, EnumeratorName)))

◆ GET_ENUMERATOR_NAME_STRING_CHECKED

#define GET_ENUMERATOR_NAME_STRING_CHECKED (   EnumName,
  EnumeratorName 
)     ((void)sizeof(UEAsserts_Private::GetMemberNameCheckedJunk(EnumName::EnumeratorName)), TEXT(#EnumeratorName))

◆ GET_ENUMERATOR_NAME_STRING_VIEW_CHECKED

#define GET_ENUMERATOR_NAME_STRING_VIEW_CHECKED (   EnumName,
  EnumeratorName 
)     ((void)sizeof(UEAsserts_Private::GetMemberNameCheckedJunk(EnumName::EnumeratorName)), TEXTVIEW(#EnumeratorName))

◆ GET_FUNCTION_NAME_CHECKED

#define GET_FUNCTION_NAME_CHECKED (   ClassName,
  FunctionName 
)     (FName(GET_FUNCTION_NAME_STRING_VIEW_CHECKED(ClassName, FunctionName)))

◆ GET_FUNCTION_NAME_CHECKED_FourParams

#define GET_FUNCTION_NAME_CHECKED_FourParams (   ClassName,
  FunctionName,
  ArgType1,
  ArgType2,
  ArgType3,
  ArgType4 
)     (FName(GET_FUNCTION_NAME_STRING_CHECKED_FourParams(ClassName, FunctionName, ArgType1, ArgType2, ArgType3, ArgType4)))

◆ GET_FUNCTION_NAME_CHECKED_OneParam

#define GET_FUNCTION_NAME_CHECKED_OneParam (   ClassName,
  FunctionName,
  ArgType 
)     (FName(GET_FUNCTION_NAME_STRING_CHECKED_OneParam(ClassName, FunctionName, ArgType)))

◆ GET_FUNCTION_NAME_CHECKED_ThreeParams

#define GET_FUNCTION_NAME_CHECKED_ThreeParams (   ClassName,
  FunctionName,
  ArgType1,
  ArgType2,
  ArgType3 
)     (FName(GET_FUNCTION_NAME_STRING_CHECKED_ThreeParams(ClassName, FunctionName, ArgType1, ArgType2, ArgType3)))

◆ GET_FUNCTION_NAME_CHECKED_TwoParams

#define GET_FUNCTION_NAME_CHECKED_TwoParams (   ClassName,
  FunctionName,
  ArgType1,
  ArgType2 
)     (FName(GET_FUNCTION_NAME_STRING_CHECKED_TwoParams(ClassName, FunctionName, ArgType1, ArgType2)))

◆ GET_FUNCTION_NAME_STRING_CHECKED

#define GET_FUNCTION_NAME_STRING_CHECKED (   ClassName,
  FunctionName 
)     ((void)sizeof(&ClassName::FunctionName), TEXT(#FunctionName))

◆ GET_FUNCTION_NAME_STRING_CHECKED_FourParams

#define GET_FUNCTION_NAME_STRING_CHECKED_FourParams (   ClassName,
  FunctionName,
  ArgType1,
  ArgType2,
  ArgType3,
  ArgType4 
)     ((void)sizeof((std::declval<ClassName&>().FunctionName(std::declval<PREPROCESSOR_REMOVE_OPTIONAL_PARENS(ArgType1)>(), std::declval<PREPROCESSOR_REMOVE_OPTIONAL_PARENS(ArgType2)>(), std::declval<PREPROCESSOR_REMOVE_OPTIONAL_PARENS(ArgType3)>(), std::declval<PREPROCESSOR_REMOVE_OPTIONAL_PARENS(ArgType4)>()), (int)0)), TEXT(#FunctionName))

◆ GET_FUNCTION_NAME_STRING_CHECKED_OneParam

#define GET_FUNCTION_NAME_STRING_CHECKED_OneParam (   ClassName,
  FunctionName,
  ArgType 
)     ((void)sizeof((std::declval<ClassName&>().FunctionName(std::declval<PREPROCESSOR_REMOVE_OPTIONAL_PARENS(ArgType)>()), (int)0)), TEXT(#FunctionName))

◆ GET_FUNCTION_NAME_STRING_CHECKED_ThreeParams

#define GET_FUNCTION_NAME_STRING_CHECKED_ThreeParams (   ClassName,
  FunctionName,
  ArgType1,
  ArgType2,
  ArgType3 
)     ((void)sizeof((std::declval<ClassName&>().FunctionName(std::declval<PREPROCESSOR_REMOVE_OPTIONAL_PARENS(ArgType1)>(), std::declval<PREPROCESSOR_REMOVE_OPTIONAL_PARENS(ArgType2)>(), std::declval<PREPROCESSOR_REMOVE_OPTIONAL_PARENS(ArgType3)>()), (int)0)), TEXT(#FunctionName))

◆ GET_FUNCTION_NAME_STRING_CHECKED_TwoParams

#define GET_FUNCTION_NAME_STRING_CHECKED_TwoParams (   ClassName,
  FunctionName,
  ArgType1,
  ArgType2 
)     ((void)sizeof((std::declval<ClassName&>().FunctionName(std::declval<PREPROCESSOR_REMOVE_OPTIONAL_PARENS(ArgType1)>(), std::declval<PREPROCESSOR_REMOVE_OPTIONAL_PARENS(ArgType2)>()), (int)0)), TEXT(#FunctionName))

◆ GET_FUNCTION_NAME_STRING_VIEW_CHECKED

#define GET_FUNCTION_NAME_STRING_VIEW_CHECKED (   ClassName,
  FunctionName 
)     ((void)sizeof(&ClassName::FunctionName), TEXTVIEW(#FunctionName))

◆ GET_MEMBER_NAME_CHECKED

#define GET_MEMBER_NAME_CHECKED (   ClassName,
  MemberName 
)     (FName(GET_MEMBER_NAME_STRING_VIEW_CHECKED(ClassName, MemberName)))

◆ GET_MEMBER_NAME_STRING_CHECKED

#define GET_MEMBER_NAME_STRING_CHECKED (   ClassName,
  MemberName 
)     ((void)sizeof(UEAsserts_Private::GetMemberNameCheckedJunk(((ClassName*)0)->MemberName)), TEXT(#MemberName))

◆ GET_MEMBER_NAME_STRING_VIEW_CHECKED

#define GET_MEMBER_NAME_STRING_VIEW_CHECKED (   ClassName,
  MemberName 
)     ((void)sizeof(UEAsserts_Private::GetMemberNameCheckedJunk(((ClassName*)0)->MemberName)), TEXTVIEW(#MemberName))

◆ LowLevelFatalError

#define LowLevelFatalError (   Format,
  ... 
)
Value:
{ \
UE_VALIDATE_FORMAT_STRING(Format, ##__VA_ARGS__); \
::UE::Assert::Private::ProcessLowLevelFatalError(__FILE__, __LINE__, Format, ##__VA_ARGS__); \
}
StaticCastSharedRef
UE_FORCEINLINE_HINT TSharedRef< CastToType, Mode > StaticCastSharedRef(TSharedRef< CastFromType, Mode > const &InSharedRef)
Definition SharedPointer.h:127

◆ PLATFORM_BREAK_IF_DESIRED

#define PLATFORM_BREAK_IF_DESIRED ( )    if (LIKELY(!GIgnoreDebugger)) { PLATFORM_BREAK(); }

◆ UE_DEBUG_BREAK_AND_PROMPT_FOR_REMOTE

#define UE_DEBUG_BREAK_AND_PROMPT_FOR_REMOTE ( )     if (!FPlatformMisc::IsDebuggerPresent()) { FPlatformMisc::PromptForRemoteDebugging(false); } UE_DEBUG_BREAK();

◆ UE_DEBUG_SECTION

#define UE_DEBUG_SECTION

◆ unimplemented

#define unimplemented ( )    { CA_ASSUME(false); }

◆ verify

#define verify (   expr)    { if(UNLIKELY(!(expr))){ CA_ASSUME(false); } }

◆ verifyf

#define verifyf (   expr,
  format,
  ... 
)    { if(UNLIKELY(!(expr))){ CA_ASSUME(false); } }

◆ verifySlow

#define verifySlow (   expr)    { if(UNLIKELY(!(expr))) { CA_ASSUME(false); } }

Function Documentation

◆ DispatchCheckVerify()

template<typename RetType = void, class InnerType , typename... ArgTypes>
RetType UE_COLD UE_DEBUG_SECTION DispatchCheckVerify ( InnerType &&  Inner,
ArgTypes const &...  Args 
)

◆ GetEnsureHandler()

CORE_API TFunction< bool(const FEnsureHandlerArgs &Args)> GetEnsureHandler ( )

◆ LowLevelFatalErrorHandler()

template<typename... ArgTypes>
UE_REWRITE void LowLevelFatalErrorHandler ( const ANSICHAR *  File,
int32  Line,
const TCHAR *  Format = TEXT(""),
ArgTypes...  Args 
)

◆ PrintScriptCallstack()

CORE_API void PrintScriptCallstack ( )

C Exposed function to print the callstack to ease debugging needs. In an editor build you can call this in the Immediate Window by doing, {,,UnrealEditor-Core}PrintScriptCallstack()

◆ SetEnsureHandler()

CORE_API TFunction< bool(const FEnsureHandlerArgs &Args)> SetEnsureHandler ( TFunction< bool(const FEnsureHandlerArgs &Args)>  EnsureHandler)

Sets the thead_local ensure handler callback returning true skips the regular ensure handling logic returns the previous handler which maybe nullptr

Variable Documentation

◆ GIgnoreDebugger

CORE_API bool GIgnoreDebugger
extern

Whether we should ignore the attached debugger.