File path:
Engine\Source\Runtime\Core\Private\Misc\CoreGlobals.cpp

Source:

IMPLEMENT_MODULE( FCoreModule, Core );


/*-----------------------------------------------------------------------------
    Global variables.
-----------------------------------------------------------------------------*/

CORE_API FFeedbackContext*  GWarn                       = nullptr;      /* User interaction and non critical warnings */
FConfigCacheIni*                GConfig                     = nullptr;      /* Configuration database cache */
ITransaction*               GUndo                       = nullptr;      /* Transaction tracker, non-NULL when a transaction is in progress */
FOutputDeviceConsole*       GLogConsole                 = nullptr;      /* Console log hook */
CORE_API FMalloc*           GMalloc                     = nullptr;      /* Memory allocator */
CORE_API FMalloc**          GFixedMallocLocationPtr = nullptr;      /* Memory allocator pointer location when PLATFORM_USES_FIXED_GMalloc_CLASS is true */

class UPropertyWindowManager*   GPropertyWindowManager  = nullptr;      /* Manages and tracks property editing windows */

/** For building call stack text dump in guard/unguard mechanism. */
TCHAR GErrorHist[16384] = TEXT("");

/** For building exception description text dump in guard/unguard mechanism. */
TCHAR GErrorExceptionDescription[4096] = TEXT( "" );

/** The error message, can be assertion message, ensure message or message from the fatal error. */
TCHAR GErrorMessage[4096] = TEXT( "" );


CORE_API const FText GYes   = LOCTEXT("Yes",    "Yes");
CORE_API const FText GNo    = LOCTEXT("No",     "No");
CORE_API const FText GTrue  = LOCTEXT("True",   "True");
CORE_API const FText GFalse = LOCTEXT("False",  "False");
CORE_API const FText GNone  = LOCTEXT("None",   "None");

/** If true, this executable is able to run all games (which are loaded as DLL's) **/
#if UE_GAME || UE_SERVER
    // In monolithic builds, implemented by the IMPLEMENT_GAME_MODULE macro or by UE4Game module.
    #if !IS_MONOLITHIC
        bool GIsGameAgnosticExe = true;
    #endif
#else
    // In monolithic Editor builds, implemented by the IMPLEMENT_GAME_MODULE macro or by UE4Game module.
    #if !IS_MONOLITHIC || !UE_EDITOR
        // Otherwise only modular editors are game agnostic.
        #if IS_PROGRAM || IS_MONOLITHIC
            bool GIsGameAgnosticExe = false;
        #else
            bool GIsGameAgnosticExe = true;
        #endif
    #endif //!IS_MONOLITHIC || !UE_EDITOR
#endif

/** When saving out of the game, this override allows the game to load editor only properties **/
bool GForceLoadEditorOnly = false;

/** Name of the core package                    **/
FName GLongCorePackageName(TEXT("/Script/Core"));
/** Name of the core package                    **/
FName GLongCoreUObjectPackageName(TEXT("/Script/CoreUObject"));

/** Disable loading of objects not contained within script files; used during script compilation */
bool GVerifyObjectReferencesOnly = false;

/** when constructing objects, use the fast path on consoles... */
bool GFastPathUniqueNameGeneration = false;

/** allow AActor object to execute script in the editor from specific entry points, such as when running a construction script */
bool GAllowActorScriptExecutionInEditor = false;

/** Forces use of template names for newly instanced components in a CDO */
bool GCompilingBlueprint = false;

/** True if we're reconstructing blueprint instances. Should never be true on cooked builds */
bool GIsReconstructingBlueprintInstances = false;

/** True if actors and objects are being re-instanced. */
bool GIsReinstancing = false;

/**
 * If true, we are running an editor script that should not prompt any dialog modal. The default value of any model will be used.
 * This is used when running a Blutility or script like Python and we don't want an OK dialog to pop while the script is running.
 * Could be set for commandlet with -RUNNINGUNATTENDEDSCRIPT
 */
bool GIsRunningUnattendedScript = false;

#if WITH_ENGINE
bool                    PRIVATE_GIsRunningCommandlet        = false;                /** Whether this executable is running a commandlet (custom command-line processing code) */
bool                    PRIVATE_GAllowCommandletRendering   = false;                /** If true, initialise RHI and set up scene for rendering even when running a commandlet. */
bool                    PRIVATE_GAllowCommandletAudio       = false;                /** If true, allow audio even when running a commandlet. */
#endif  // WITH_ENGINE

#if WITH_EDITORONLY_DATA
bool                    GIsEditor                       = false;                    /* Whether engine was launched for editing */
bool                    GIsImportingT3D                 = false;                    /* Whether editor is importing T3D */
bool                    GIsUCCMakeStandaloneHeaderGenerator = false;                /* Are we rebuilding script via the standalone header generator? */
bool                    GIsTransacting                  = false;                    /* true if there is an undo/redo operation in progress. */
bool                    GIntraFrameDebuggingGameThread  = false;                    /* Indicates that the game thread is currently paused deep in a call stack; do not process any game thread tasks */
bool                    GFirstFrameIntraFrameDebugging  = false;                    /* Indicates that we're currently processing the first frame of intra-frame debugging */
#elif USING_CODE_ANALYSIS
// These are always false during 'non-editor code analysis', just like they would be when #defined.
bool                    GIsEditor                       = false;
bool                    GIsUCCMakeStandaloneHeaderGenerator = false;
bool                    GIntraFrameDebuggingGameThread  = false;
bool                    GFirstFrameIntraFrameDebugging  = false;
#endif // !WITH_EDITORONLY_DATA

bool                    GEdSelectionLock                = false;                    /* Are selections locked? (you can't select/deselect additional actors) */
bool                    GIsClient                       = false;                    /* Whether engine was launched as a client */
bool                    GIsServer                       = false;                    /* Whether engine was launched as a server, true if GIsClient */
bool                    GIsCriticalError                = false;                    /* An appError() has occured */
bool                    GIsGuarded                      = false;                    /* Whether execution is happening within main()/WinMain()'s try/catch handler */
TSAN_ATOMIC(bool)       GIsRunning(false);                                          /* Whether execution is happening within MainLoop() */
bool                    GIsDuplicatingClassForReinstancing = false;                 /* Whether we are currently using SDO on a UClass or CDO for live reinstancing */
/** This specifies whether the engine was launched as a build machine process                               */
bool                    GIsBuildMachine                 = false;
/** This determines if we should output any log text.  If Yes then no log text should be emitted.           */
bool                    GIsSilent                       = false;
bool                    GIsSlowTask                     = false;                    /* Whether there is a slow task in progress */
bool                    GSlowTaskOccurred               = false;                    /* Whether a slow task began last tick*/
bool                    GIsRequestingExit               = false;                    /* Indicates that MainLoop() should be exited at the end of the current iteration */
/** Archive for serializing arbitrary data to and from memory                                               */
bool                    GAreScreenMessagesEnabled       = true;                     /* Whether onscreen warnings/messages are enabled */
bool                    GScreenMessagesRestoreState     = false;                    /* Used to restore state after a screenshot */
int32                   GIsDumpingMovie                 = 0;                        /* Whether we are dumping screenshots (!= 0), exposed as console variable r.DumpingMovie */
bool                    GIsHighResScreenshot            = false;                    /* Whether we're capturing a high resolution shot */
uint32                  GScreenshotResolutionX          = 0;                        /* X Resolution for high res shots */
uint32                  GScreenshotResolutionY          = 0;                        /* Y Resolution for high res shots */
uint64                  GMakeCacheIDIndex               = 0;                        /* Cache ID */

FString             GEngineIni;                                                 /* Engine ini filename */

/** Editor ini file locations - stored per engine version (shared across all projects). Migrated between versions on first run. */
FString             GEditorIni;                                                 /* Editor ini filename */
FString             GEditorKeyBindingsIni;                                      /* Editor Key Bindings ini file */
FString             GEditorLayoutIni;                                           /* Editor UI Layout ini filename */
FString             GEditorSettingsIni;                                         /* Editor Settings ini filename */

/** Editor per-project ini files - stored per project. */
FString             GEditorPerProjectIni;                                       /* Editor User Settings ini filename */

FString             GCompatIni;
FString             GLightmassIni;                                              /* Lightmass settings ini filename */
FString             GScalabilityIni;                                            /* Scalability settings ini filename */
FString             GHardwareIni;                                               /* Hardware ini filename */
FString             GInputIni;                                                  /* Input ini filename */
FString             GGameIni;                                                   /* Game ini filename */
FString             GGameUserSettingsIni;                                       /* User Game Settings ini filename */

float                   GNearClippingPlane              = 10.0f;                /* Near clipping plane */

bool                    GExitPurge                      = false;

FChunkedFixedUObjectArray* GCoreObjectArrayForDebugVisualizers = nullptr;
#if PLATFORM_UNIX
FNameEntry*** CORE_API GFNameTableForDebuggerVisualizers_MT = FName::GetNameTableForDebuggerVisualizers_MT();
FChunkedFixedUObjectArray*& CORE_API GObjectArrayForDebugVisualizers = GCoreObjectArrayForDebugVisualizers;
#endif

/** Game name, used for base game directory and ini among other things                                      */
#if (!IS_MONOLITHIC && !IS_PROGRAM)
// In modular game builds, the game name will be set when the application launches
TCHAR                   GInternalProjectName[64]                    = TEXT("None");
#elif !IS_MONOLITHIC && IS_PROGRAM
// In non-monolithic programs builds, the game name will be set by the module, but not just yet, so we need to NOT initialize it!
TCHAR                   GInternalProjectName[64];
#else
// For monolithic builds, the game name variable definition will be set by the IMPLEMENT_GAME_MODULE
// macro for the game's main game module.
#endif

// Foreign engine directory. This is required to projects built outside the engine root to reference their engine directory.
#if !IS_MONOLITHIC
IMPLEMENT_FOREIGN_ENGINE_DIR()
#endif

/** A function that does nothing. Allows for a default behavior for callback function pointers. */
static void appNoop()
{
}

/** Exec handler for game debugging tool, allowing commands like "editactor", ...                           */
FExec*                  GDebugToolExec                  = NULL;
/** Whether we're currently in the async loading codepath or not                                            */
static bool IsAsyncLoadingCoreInternal()
{
    // No Async loading in Core
    return false;
}
bool (*IsAsyncLoading)() = &IsAsyncLoadingCoreInternal;
void (*SuspendAsyncLoading)() = &appNoop;
void (*ResumeAsyncLoading)() = &appNoop;
bool (*IsAsyncLoadingSuspended)() = &IsAsyncLoadingCoreInternal;
bool (*IsAsyncLoadingMultithreaded)() = &IsAsyncLoadingCoreInternal;
void (*SuspendTextureStreamingRenderTasks)() = &appNoop;
void (*ResumeTextureStreamingRenderTasks)() = &appNoop;

/** Whether the editor is currently loading a package or not                                                */
bool                    GIsEditorLoadingPackage             = false;
/** Whether the cooker is currently loading a package or not                                                */
bool                    GIsCookerLoadingPackage = false;
/** Whether GWorld points to the play in editor world                                                       */
bool                    GIsPlayInEditorWorld            = false;
/** Unique ID for multiple PIE instances running in one process */
int32                   GPlayInEditorID                 = -1;
/** Whether or not PIE was attempting to play from PlayerStart                          */
bool                    GIsPIEUsingPlayerStart          = false;
/** true if the runtime needs textures to be powers of two                                                  */
bool                    GPlatformNeedsPowerOfTwoTextures = false;
/** Time at which FPlatformTime::Seconds() was first initialized (before main)                                          */
double                  GStartTime                      = FPlatformTime::InitTiming();
/** System time at engine init.                                                                             */
FString                 GSystemStartTime;
/** Whether we are still in the initial loading proces.                                                     */
bool                    GIsInitialLoad                  = true;
/* Whether we are using the event driven loader */
bool                    GEventDrivenLoaderEnabled = false;

/** Steadily increasing frame counter.                                                                      */
TSAN_ATOMIC(uint64)     GFrameCounter(0);
uint64                  GLastGCFrame                    = 0;
/** Incremented once per frame before the scene is being rendered. In split screen mode this is incremented once for all views (not for each view). */
uint32                  GFrameNumber                    = 1;
/** NEED TO RENAME, for RT version of GFrameTime use View.ViewFamily->FrameNumber or pass down from RT from GFrameTime). */
uint32                  GFrameNumberRenderThread        = 1;
#if !(UE_BUILD_SHIPPING && WITH_EDITOR)
// We cannot count on this variable to be accurate in a shipped game, so make sure no code tries to use it
/** Whether we are the first instance of the game running.                                                  */
#if !PLATFORM_UNIX
bool                    GIsFirstInstance                = true;
#endif
#endif
/** Threshold for a frame to be considered a hitch (in milliseconds). */
float GHitchThresholdMS = 60.0f;
/** Size to break up data into when saving compressed data                                                  */
int32                   GSavingCompressionChunkSize     = SAVING_COMPRESSION_CHUNK_SIZE;
/** Thread ID of the main/game thread                                                                       */
uint32                  GGameThreadId                   = 0;
uint32                  GRenderThreadId                 = 0;
uint32                  GSlateLoadingThreadId           = 0;
uint32                  GAudioThreadId                  = 0;
/** Has GGameThreadId been set yet?                                                                         */
bool                    GIsGameThreadIdInitialized      = false;

/** Helper function to flush resource streaming.                                                            */
void                    (*GFlushStreamingFunc)(void)      = &appNoop;
/** Whether to emit begin/ end draw events.                                                                 */
bool                    GEmitDrawEvents                 = false;
/** Whether forward DrawEvents to the RHI or keep them only on the Commandlist. */
bool                    GCommandListOnlyDrawEvents      = false;
/** Whether we want the rendering thread to be suspended, used e.g. for tracing.                            */
bool                    GShouldSuspendRenderingThread   = false;
/** Determines what kind of trace should occur, NAME_None for none.                                         */
FName                   GCurrentTraceName               = NAME_None;
/** How to print the time in log output                                                                     */
ELogTimes::Type         GPrintLogTimes                  = ELogTimes::None;
/** How to print the category in log output. */
bool                    GPrintLogCategory = true;
/** How to print the verbosity in log output. */
bool                    GPrintLogVerbosity = true;

#if USE_HITCH_DETECTION
bool                GHitchDetected = false;
#endif

/** Whether stats should emit named events for e.g. PIX.                                                    */
int32                   GCycleStatsShouldEmitNamedEvents = 0;
/** Disables some warnings and minor features that would interrupt a demo presentation                      */
bool                    GIsDemoMode                     = false;
/** Whether or not a unit test is currently being run                                                       */
bool                    GIsAutomationTesting                    = false;
/** Whether or not messages are being pumped outside of the main loop                                       */
bool                    GPumpingMessagesOutsideOfMainLoop = false;

/** Enables various editor and HMD hacks that allow the experimental VR editor feature to work, perhaps at the expense of other systems */
bool                    GEnableVREditorHacks = false;

bool CORE_API           GIsGPUCrashed = false;

bool GetEmitDrawEvents()
{
    return GEmitDrawEvents;
}

void CORE_API SetEmitDrawEvents(bool EmitDrawEvents)
{
    GEmitDrawEvents = EmitDrawEvents;
    GCommandListOnlyDrawEvents = !GEmitDrawEvents;
}

void CORE_API EnableEmitDrawEventsOnlyOnCommandlist()
{
    GCommandListOnlyDrawEvents = !GEmitDrawEvents;
    GEmitDrawEvents = true;
}

void ToggleGDebugPUCrashedFlag(const TArray<FString>& Args)
{
    GIsGPUCrashed = !GIsGPUCrashed;
    UE_LOG(LogCore, Log, TEXT("Gpu crashed flag forcibly set to: %i"), GIsGPUCrashed ? 1 : 0);
}

FAutoConsoleCommand ToggleDebugGPUCrashedCmd(
    TEXT("c.ToggleGPUCrashedFlagDbg"),
    TEXT("Forcibly toggles the 'GPU Crashed' flag for testing crash analytics."),
    FConsoleCommandWithArgsDelegate::CreateStatic(&ToggleGDebugPUCrashedFlag),
    ECVF_Cheat);

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