Esempi di traccia C/C++

Articolo
06/13/2023

Questo argomento contiene esempi di tracelogging C/C++ usando TraceLoggingWrite.

Registrare tipi di dati semplici
Campi evento name
Livello di dettaglio degli eventi di log
Parole chiave degli eventi di log
Dati degli eventi della matrice di log
Dati degli eventi della struttura di log

Questi esempi presuppongono che il programma sia stato configurato correttamente per TraceLogging:

Inclusa l'intestazione TraceLoggingProvider.h .
Definito un g_hMyComponentProvider oggetto using TRACELOGGING_DEFINE_PROVIDER.
Registrato il provider all'avvio del programma usando TraceLoggingRegister.
Annulla la registrazione del provider all'uscita del programma tramite TraceLoggingUnregister.

#include <windows.h>
#include <TraceLoggingProvider.h>
#include <winmeta.h> // Define constants e.g. WINEVENT_LEVEL_VERBOSE

// Define the GUID to use in TraceLoggingProviderRegister
TRACELOGGING_DEFINE_PROVIDER(
    g_hMyComponentProvider,
    "SimpleTraceLoggingProvider",
    // {0205c616-cf97-5c11-9756-56a2cee02ca7}
    (0x0205c616,0xcf97,0x5c11,0x97,0x56,0x56,0xa2,0xce,0xe0,0x2c,0xa7));

// The following example functions are defined later in this topic.
void SimpleDataTypes();
void NamingData();
void LevelsAndKeywords();
void CombineKeywords();
void Arrays();
void Structs();

void main()
{
    // Register the provider
    TraceLoggingRegister(g_hMyComponentProvider);

    // Log events using the g_hMyComponentProvider handle...
    SimpleDataTypes();
    NamingData();
    LevelsAndKeywords();
    CombineKeywords();
    Arrays();
    Structs();

    // Stop TraceLogging and unregister the provider
    TraceLoggingUnregister(g_hMyComponentProvider);
}

Importante

Per evitare errori del linker per le funzioni , EventWriteTransfero EventUnregister non risolteEventRegister, collegarsi con advapi32.lib durante la compilazione di questi esempi.

Per raccogliere e decodificare gli eventi da questi esempi, è necessario avviare una traccia usando uno strumento come tracelog o traceview, eseguire l'esempio, arrestare la traccia usando uno strumento come tracelog o traceview e decodificare la traccia usando uno strumento di decodifica come tracefmt o traceview. Ad esempio, se il provider è stato definito usando GUID {0205c616-cf97-5c11-9756-56a2cee02ca7}, è possibile visualizzare gli eventi di questi esempi usando il tracelog degli strumenti di Windows SDK e tracefmt come indicato di seguito:

tracelog -start MyTraceSession -f MyTraceFile.etl -guid #0205c616-cf97-5c11-9756-56a2cee02ca7
Eseguire l'esempio.
tracelog -stop MyTraceSession
tracefmt -o MyTraceFile.txt MyTraceFile.etl
notepad MyTraceFile.txt

Registrare tipi di dati semplici

In questo esempio viene illustrato come registrare tipi di dati semplici, ad esempio interi, booleani e così via.

void SimpleDataTypes()
{
    UINT8 u8 = 200;
    INT32 i32 = -2000000000;
    UINT32 u32 = 4000000000;
    INT64 i64 = 9000000000000000000;
    float f32 = 3.14f;
    BOOL b = TRUE;
    bool bcpp = true;

    TraceLoggingWrite(
        g_hMyComponentProvider,
        "NumericValues",
        TraceLoggingUInt8(u8, "MyByteValue"),
        TraceLoggingInt32(i32, "MyIntValue"),
        TraceLoggingUInt32(u32, "MyUInt"),
        TraceLoggingHexUInt32(u32, "MyHexValue"),
        TraceLoggingInt64(i64, "MyBigValue"),
        TraceLoggingFloat32(f32, "MyFloat"),
        TraceLoggingBool(b, "MyBool32"),
        TraceLoggingBoolean(bcpp, "MyC++Boolean")
        );

#ifdef __cplusplus

    /*
    TraceLoggingValue() automatically determines the value type (C++ only).
    In many cases, TraceLoggingValue() can be used instead of a more specific macro.
    */

    TraceLoggingWrite(
        g_hMyComponentProvider,
        "NumericValues",
        TraceLoggingValue(u8, "MyByteValue"),
        TraceLoggingValue(i32, "MyIntValue"),
        TraceLoggingValue(u32, "MyUInt"),
        TraceLoggingHexUInt32(u32, "MyHexValue"), // TraceLoggingValue won't format as hexadecimal.
        TraceLoggingValue(i64, "INT64"),
        TraceLoggingValue(f32, "float"),
        TraceLoggingBool(b, "BOOL"), // TraceLoggingValue considers BOOL the same as int.
        TraceLoggingValue(bcpp, "bool (C++)") // But bool is a distinct type so this works ok.
        );

#endif

    /*
    Strings and chars
    */

    TraceLoggingWrite(
        g_hMyComponentProvider,
        "Strings and Chars",
        TraceLoggingString("String1", "String (char)"),
        TraceLoggingWideString(L"LString2", "String (wide char)"),
        TraceLoggingChar('A', "Single char")
        );

    /*
    Other types
    */

    /*
    NOTE: In C, a GUID, FILETIME, or SYSTEMTIME value parameter must be an l-value.
    */

    INT_PTR iptr = 1234;
    UINT_PTR uptr = 4321;
    FILETIME ft;
    SYSTEMTIME st;
    SID const sid1 = { SID_REVISION, 1, 5, { 6 } };
    static const GUID s_TestGuid = { 0x3970f9cf, 0x2c0c, 0x4f11, { 0xb1, 0xcc, 0xe3, 0xa1, 0xe9, 0x95, 0x88, 0x33 } };

    GetSystemTime(&st);
    GetSystemTimeAsFileTime(&ft);

    TraceLoggingWrite(
        g_hMyComponentProvider,
        "Other Types",
        TraceLoggingGuid(s_TestGuid, "GUID"),
        TraceLoggingSystemTime(st, "Current Time (FILETIME)"),
        TraceLoggingPointer(&iptr, "Pointer value"), // Logs the pointer value, not the data.
        TraceLoggingSid(&sid1, "SID")
        TraceLoggingIntPtr(iptr, "INT_PTR"),
        TraceLoggingUIntPtr(uptr, "UINT_PTR")
        );
}

Campi evento name

Nell'esempio viene illustrato come assegnare un nome ai campi evento.

void NamingData()
{
    UINT32 Cat = 0xCA7;

    /*
    Each of the following four events are equivalent:
    */

    /*
    TraceLogging uses the symbol to automatically name the field "Cat"
    and assign it the value contained in the variable Cat (0xCA7).
    */

    TraceLoggingWrite(
        g_hMyComponentProvider,
        "Cat1",
        TraceLoggingUInt32(Cat) // Field is automatically named "Cat"
        );

    TraceLoggingWrite(
        g_hMyComponentProvider,
        "Cat2",
        TraceLoggingValue(Cat) // Field is automatically named "Cat"
        );


    /*
    Use a different symbol for the value of the event's "Cat" field.
    */

    UINT32 Tiger = Cat;

    /*
    Now we need to explicitly name the datum or we will have events with a
    different field name ("Tiger").
    */

    TraceLoggingWrite(
        g_hMyComponentProvider,
        "Tiger",
        TraceLoggingUInt32(Tiger, "Cat") // Field is explicitly named "Cat".
        );

    TraceLoggingWrite(
        g_hMyComponentProvider,
        "Cat3",
        TraceLoggingValue(Tiger, "Cat") // Field is explicitly named "Cat".
        );
};

Livello di verbosità degli eventi di log

In questo esempio viene illustrato come registrare gli eventi in base al livello di verbosità.

#include <winmeta.h> // for WINEVENT_LEVEL_* definitions
void LevelsAndKeywords()
{
    /*
    Verbosity levels and event keywords must be compile-time constants.
    If TraceLoggingLevel is not used, the default is 5 (VERBOSE).
    If TraceLoggingKeyword is not used, the defualt is 0 (no categories).

    TraceLoggingLevel accepts values 0-255.
    TraceLoggingKeyword accepts values 0 to UINT64_MAX. Each bit is a category.

    Level and keyword are the primary system for filtering events. All events
    should have a meaningful (non-zero) level and keyword to enable filtering.
    See winmeta.h for predefined verbosity levels and reserved keyword values.
    */

    PCWSTR MyName = L"Joe";
    INT16 MyRank = 99;
    ULONG MySerialNumber = 12345;

    /*
    The following is only logged when session verbosity level is
    WINEVENT_LEVEL_VERBOSE (5) or higher ...
    */

    TraceLoggingWrite(
        g_hMyComponentProvider,
        "Levels",
        TraceLoggingLevel(WINEVENT_LEVEL_VERBOSE),
        TraceLoggingWideString(MyName, "Name"),
        TraceLoggingInt16(MyRank, "Rank"),
        TraceLoggingUInt32(MySerialNumber, "Serial Number")
        );

    /*
    TraceLoggingWrite will not complain if TraceLoggingLevel is invoked more than once.
    However, only the last level will be used.
    The following event is only logged at WINEVENT_LEVEL_VERBOSE or higher...
    */

    TraceLoggingWrite(
        g_hMyComponentProvider,
        "Levels",
        TraceLoggingLevel(WINEVENT_LEVEL_CRITICAL),
        TraceLoggingLevel(WINEVENT_LEVEL_VERBOSE),
        TraceLoggingWideString(MyName, "Name"),
        TraceLoggingInt16(MyRank, "Rank"),
        TraceLoggingUInt32(MySerialNumber, "Serial Number")
        );
}

Parole chiave dell'evento di log

In questo esempio viene illustrato come impostare parole chiave evento. È possibile eseguire il filtro degli eventi in base al livello e alla parola chiave. Ad esempio, gli eventi di completamento dello scenario o gli eventi di errore potrebbero essere raggruppati in parole chiave separate in modo che sia possibile filtrare facilmente tali eventi.

void CombineKeywords()
{
    /*
    Keywords can be combined using multiple TraceLoggingKeyword() macros ...
    */

    #define MY_PROVIDER_KEYWORD_BLUE    0x1
    #define MY_PROVIDER_KEYWORD_YELLOW  0x2
    #define MY_PROVIDER_KEYWORD_GREEN   (MY_PROVIDER_KEYWORD_BLUE | MY_PROVIDER_KEYWORD_YELLOW)

    PCWSTR Status = L"Feeling a bit green";

    /*
    These events are equivalent...
    */

    TraceLoggingWrite(
        g_hProvider,
        "Keywords",
        TraceLoggingKeyword(MY_PROVIDER_KEYWORD_GREEN),
        TraceLoggingValue(Status, "Current Status")
        );

    TraceLoggingWrite(
        g_hProvider,
        "Keywords",
        TraceLoggingKeyword(MY_PROVIDER_KEYWORD_BLUE | MY_PROVIDER_KEYWORD_YELLOW),
        TraceLoggingValue(Status, "Current Status")
        );

    TraceLoggingWrite(
        g_hProvider,
        "Keywords",
        TraceLoggingKeyword(MY_PROVIDER_KEYWORD_BLUE),
        TraceLoggingKeyword(MY_PROVIDER_KEYWORD_YELLOW),
        TraceLoggingValue(Status, "Current Status")
        );
}

Dati degli eventi della matrice di log

In questo esempio viene illustrato come registrare le matrici come dati dell'evento.

void Arrays()
{
    INT32 IntValsFixed[5] = {20, 21, 22, 23, 24};
    UINT cIntVals = 5;
    INT32* IntValsVar = new INT32[cIntVals];

    VERIFY_IS_NOT_NULL(IntValsVar);
    memcpy(IntValsVar, IntValsFixed, sizeof(IntValsFixed));


    /*
    Variable size arrays
    */

    TraceLoggingWrite(
        g_hMyComponentProvider,
        "Variable Size Arrays",
        TraceLoggingInt32Array(IntValsVar, (UINT16)cIntVals, "Variable size int array"),
        TraceLoggingInt32Array(IntValsVar, 5, "Variable size int array")
        );

    /*
    Fixed size arrays

    Fixed size array macros use the "FixedArray" suffix.
    The absence of the suffix indicates a variable sized array.
    */

    TraceLoggingWrite(
        g_hMyComponentProvider,
        "Constant Size Arrays",
        TraceLoggingInt32FixedArray(IntValsFixed, _countof(IntValsFixed), "Constant size int array")
        );

    delete [] IntValsVar;
}

Dati degli eventi della struttura di log

In questo esempio viene illustrato come registrare i dati degli eventi della struttura.

void Structs()
{
    WIN32_FIND_DATA FindData;
    HANDLE hFind = FindFirstFile(".", &FindData);

    VERIFY_IS_TRUE(hFind != INVALID_HANDLE_VALUE);

    /*
    TraceLoggingStruct defines a group of related fields in an event.
    The first parameter, which must be a compile-time constant, indicates
    the number of subsequent fields that are to be considered part of the
    struct.
    */

    TraceLoggingWrite(
        g_hMyComponentProvider,
        "FindFirstFile",
        TraceLoggingStruct(5, "FileData"),
            TraceLoggingString(FindData.cFileName, "Name"),
            TraceLoggingUInt32(FindData.dwFileAttributes, "Attributes"),
            TraceLoggingFileTime(FindData.ftCreationTime, "CreateTime"),
            TraceLoggingUInt32(FindData.nFileSizeHigh, "SizeHigh"),
            TraceLoggingUInt32(FindData.nFileSizeLow, "SizeLow"),
        TraceLoggingPointer(hFind, "Result")
        );

    /*
    ... or ...
    */

#define LogWin32FindData(fd) \
    TraceLoggingStruct(5, "FileData"), \
    TraceLoggingString(((fd).cFileName), "Name"), \
    TraceLoggingUInt32(((fd).dwFileAttributes), "Attributes"), \
    TraceLoggingFileTime(((fd).ftCreationTime), "CreateTime"), \
    TraceLoggingUInt32(((fd).nFileSizeHigh), "SizeHigh"), \
    TraceLoggingUInt32(((fd).nFileSizeLow), "SizeLow")

    TraceLoggingWrite(
        g_hMyComponentProvider,
        "FindFirstFile",
        LogWin32FindData(FindData),
        TraceLoggingPointer(hFind, "Result")
        );

    FindClose(hFind);
}

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