Ошибка 1 error lnk1561 точка входа должна быть определена

Вот мой код:

#include <iostream>
#include <cmath>
using namespace std;

int main()
{
    int x;
    int y = pow(2, x);
    cin>>x;
    cout<< y;
    system("pause");
    return 0;
}

Почему я получаю ошибку компиляции? LNK1561 entry point must be defined

Я использую Visual Studio Express.

Вам нужно присвоить значение x перед его использованием

int x;
int y = pow(2, x); // <--- what is the value of x here?

Сначала попробуйте получить значение x из ввода.

#include <iostream>
#include <cmath>
using namespace std;
int main()
{
    int x;
    cin >> x;
    int y = pow(2, x);
    cout<< y; 
    system("pause");
    return 0;
}

#include <iostream>
#include <cmath>
using namespace std;
int main()
{
    int x;
    //int y = pow(2, x);//(1)
    //cin>>x;//(2)

    //exchange the lines (2) and (1)
    cin>>x;//(2)
    int y = pow(2, x);//(1)
    cout<< y; 
    system("pause");
    return 0;
}

Я создал пустой проект Visual C ++ с Visual Studio 2017 15.3.4 Редакция сообщества, выбрав Visual C ++ -> Общие -> Пустой проект из мастера. Я хотел создать библиотеку C ++ (статическую или динамическую).

Но когда я компилирую это, я получаю это сообщение:

ССЫЛКА: фатальная ошибка LNK1561: должна быть определена точка входа

Я щелкнул правой кнопкой мыши на Project, выберите Properties, Linker и Advanced, и опция Entry Point пуста.

Что я должен положить туда?

Есть ли еще лучший вариант для создания библиотеки C ++?

2

Библиотека не имеет точки входа, поэтому вы можете сказать, что проект настроен неправильно. Конкретный параметр, который вы забыли изменить, — это «Проект»> «Свойства»> «Основные»> «Тип конфигурации». Выберите «Статическая библиотека (.lib)».

Это пошло не так, потому что вы начали с нуля, правильная настройка десятков настроек никогда не была проблемой. Для VS2017 RTM вы предпочитаете начинать с Win32> Win32 Project> Next> «Статическая библиотека». Возможно, это изменилось, я не обновлял его, потому что видел слишком много неприятных отчетов об ошибках для 15.3.x

1

Чтобы создать статическую библиотеку в VS 2017 версии 15.3.4, сначала выберите шаблон «Мастер рабочего стола Windows»,

В появившемся диалоговом окне мастера измените тип приложения на статическую библиотеку:

Вы также можете отключить предварительно скомпилированные заголовки, поскольку в Visual C ++ это дает нестандартное поведение препроцессора.

2

All replies

• Raleigh77 wrote:

  I am trying to make an executable from source code, headers, etc.

  LINK : fatal error LNK1561: entry point must be defined

  You haven’t defined a function named main or wmain or WinMain or  wWinMain.

  ---

  Igor Tandetnik

• If please possible quote the program or just the part of program which consist your entry point of your program. i.e. the part of program having the Main() fuction is it is a console program, the cmd type. or WinMain() function
  if a windows program. If there isn’t one such function then thats is your problem. Your program must have a entry point fuction in other words the function from which your program starts. There might be a possibilty you might have misstyped the fuction name
  incorrectly.

  • Proposed as answer by

    Tuesday, November 22, 2011 4:39 AM

• >There might be a possibilty you might have misstyped
  >the fuction name incorrectly.

  <evil grin> As you did when you typed:

  >…the part of program which consist your entry point
  >of your program. i.e. the part of program having the
  >Main() fuction is it is a console program …

  It should be: «main() function …»

  C and C++ are case-sensitive languages. The names
  «main» and «Main» are not the same.

  — Wayne

  • Proposed as answer by
    detectivecalcite
    Thursday, October 4, 2012 6:14 AM

• Thanks.

  This came from here.

  http://msdn.microsoft.com/en-us/library/aa363680%28v=vs.85%29.aspx

  Andy

  // report_event
  #ifndef UNICODE
  #define UNICODE
  #endif
  #include <windows.h>
  #include <stdio.h>
  #include «provider.h»

  #pragma comment(lib, «advapi32.lib»)

  #define PROVIDER_NAME L»MyEventProvider»

  // Hardcoded insert string for the event messages.
  CONST LPWSTR pBadCommand = L»The command that was not valid»;
  CONST LPWSTR pFilename = L»c:\folder\file.ext»;
  CONST LPWSTR pNumberOfRetries = L»3″;
  CONST LPWSTR pSuccessfulRetries = L»0″;
  CONST LPWSTR pQuarts = L»8″;
  CONST LPWSTR pGallons = L»2″;

  void wmain(void)
  {
      HANDLE hEventLog = NULL;
      LPWSTR pInsertStrings[2] = {NULL, NULL};
      DWORD dwEventDataSize = 0;

      // The source name (provider) must exist as a subkey of Application.
      hEventLog = RegisterEventSource(NULL, PROVIDER_NAME);
      if (NULL == hEventLog)
      {
          wprintf(L»RegisterEventSource failed with 0x%x.n», GetLastError());
          goto cleanup;
      }

      // This event includes user-defined data as part of the event. The event message
      // does not use insert strings.
      dwEventDataSize = ((DWORD)wcslen(pBadCommand) + 1) * sizeof(WCHAR);
      if (!ReportEvent(hEventLog, EVENTLOG_ERROR_TYPE, UI_CATEGORY, MSG_INVALID_COMMAND, NULL, 0, dwEventDataSize, NULL, pBadCommand))
      {
          wprintf(L»ReportEvent failed with 0x%x for event 0x%x.n», GetLastError(), MSG_INVALID_COMMAND);
          goto cleanup;
      }

      // This event uses insert strings.
      pInsertStrings[0] = pFilename;
      if (!ReportEvent(hEventLog, EVENTLOG_ERROR_TYPE, DATABASE_CATEGORY, MSG_BAD_FILE_CONTENTS, NULL, 1, 0, (LPCWSTR*)pInsertStrings, NULL))
      {
          wprintf(L»ReportEvent failed with 0x%x for event 0x%x.n», GetLastError(), MSG_BAD_FILE_CONTENTS);
          goto cleanup;
      }

      // This event uses insert strings.
      pInsertStrings[0] = pNumberOfRetries;
      pInsertStrings[1] = pSuccessfulRetries;
      if (!ReportEvent(hEventLog, EVENTLOG_WARNING_TYPE, NETWORK_CATEGORY, MSG_RETRIES, NULL, 2, 0, (LPCWSTR*)pInsertStrings, NULL))
      {
          wprintf(L»ReportEvent failed with 0x%x for event 0x%x.n», GetLastError(), MSG_RETRIES);
          goto cleanup;
      }

      // This event uses insert strings.
      pInsertStrings[0] = pQuarts;
      pInsertStrings[1] = pGallons;
      if (!ReportEvent(hEventLog, EVENTLOG_INFORMATION_TYPE, UI_CATEGORY, MSG_COMPUTE_CONVERSION, NULL, 2, 0, (LPCWSTR*)pInsertStrings, NULL))
      {
          wprintf(L»ReportEvent failed with 0x%x for event 0x%x.n», GetLastError(), MSG_COMPUTE_CONVERSION);
          goto cleanup;
      }

      wprintf(L»All events successfully reported.n»);

  cleanup:

      if (hEventLog)
          DeregisterEventSource(hEventLog);
  }

• I am using Visual Studio 10.0.

  I get this message.

  LINK : fatal error LNK1561: entry point must be defined

  The code came from here.

  http://msdn.microsoft.com/en-us/library/aa363680%28v=vs.85%29.aspx

  Could someone help me with this problem?

  Thanks.

  // report_event
  #ifndef UNICODE
  #define UNICODE
  #endif
  #include <windows.h>
  #include <stdio.h>
  #include «provider.h»

  #pragma comment(lib, «advapi32.lib»)

  #define PROVIDER_NAME L»MyEventProvider»

  // Hardcoded insert string for the event messages.
  CONST LPWSTR pBadCommand = L»The command that was not valid»;
  CONST LPWSTR pFilename = L»c:\folder\file.ext»;
  CONST LPWSTR pNumberOfRetries = L»3″;
  CONST LPWSTR pSuccessfulRetries = L»0″;
  CONST LPWSTR pQuarts = L»8″;
  CONST LPWSTR pGallons = L»2″;

  void wmain(void)
  {
      HANDLE hEventLog = NULL;
      LPWSTR pInsertStrings[2] = {NULL, NULL};
      DWORD dwEventDataSize = 0;

      // The source name (provider) must exist as a subkey of Application.
      hEventLog = RegisterEventSource(NULL, PROVIDER_NAME);
      if (NULL == hEventLog)
      {
          wprintf(L»RegisterEventSource failed with 0x%x.n», GetLastError());
          goto cleanup;
      }

      // This event includes user-defined data as part of the event. The event message
      // does not use insert strings.
      dwEventDataSize = ((DWORD)wcslen(pBadCommand) + 1) * sizeof(WCHAR);
      if (!ReportEvent(hEventLog, EVENTLOG_ERROR_TYPE, UI_CATEGORY, MSG_INVALID_COMMAND, NULL, 0,

  dwEventDataSize, NULL, pBadCommand))
      {
          wprintf(L»ReportEvent failed with 0x%x for event 0x%x.n», GetLastError(),

  MSG_INVALID_COMMAND);
          goto cleanup;
      }

      // This event uses insert strings.
      pInsertStrings[0] = pFilename;
      if (!ReportEvent(hEventLog, EVENTLOG_ERROR_TYPE, DATABASE_CATEGORY, MSG_BAD_FILE_CONTENTS,

  NULL, 1, 0, (LPCWSTR*)pInsertStrings, NULL))
      {
          wprintf(L»ReportEvent failed with 0x%x for event 0x%x.n», GetLastError(),

  MSG_BAD_FILE_CONTENTS);
          goto cleanup;
      }

      // This event uses insert strings.
      pInsertStrings[0] = pNumberOfRetries;
      pInsertStrings[1] = pSuccessfulRetries;
      if (!ReportEvent(hEventLog, EVENTLOG_WARNING_TYPE, NETWORK_CATEGORY, MSG_RETRIES, NULL, 2, 0,

  (LPCWSTR*)pInsertStrings, NULL))
      {
          wprintf(L»ReportEvent failed with 0x%x for event 0x%x.n», GetLastError(), MSG_RETRIES);
          goto cleanup;
      }

      // This event uses insert strings.
      pInsertStrings[0] = pQuarts;
      pInsertStrings[1] = pGallons;
      if (!ReportEvent(hEventLog, EVENTLOG_INFORMATION_TYPE, UI_CATEGORY, MSG_COMPUTE_CONVERSION,

  NULL, 2, 0, (LPCWSTR*)pInsertStrings, NULL))
      {
          wprintf(L»ReportEvent failed with 0x%x for event 0x%x.n», GetLastError(),

  MSG_COMPUTE_CONVERSION);
          goto cleanup;
      }

      wprintf(L»All events successfully reported.n»);

  cleanup:

      if (hEventLog)
          DeregisterEventSource(hEventLog);
  }

  • Merged by
    lucy-liu
    Wednesday, February 9, 2011 3:11 AM
    Merge them to keep in the same topic

• Configuration Properties, Linker, System, SubSystem => set to Console (/SUBSYSTEM:CONSOLE)

• Configuration Properties, Linker, System, SubSystem => set to Console (/SUBSYSTEM:CONSOLE)

  Duplicate post.

• Thanks.

  I uninstalled V.S. because of the difficulty of using it.

  I used the Pro version, and it took about 6 hrs. to download and install.

  I am rethinking if it would be worth the time and effort for what I would probably use

  for only one C ++ source.

  I currently use masm and it’s linker to produce 32 bit programs using assembly source code.

  Andy

• Hi Raleigh77,

  Have you solved your issue?

  If you have solved, please mark the useful reply as answer.

  Best regards,

  Lucy

  ---

  Lucy Liu [MSFT]
  MSDN Community Support | Feedback to us
  Get or Request Code Sample from Microsoft
  Please remember to mark the replies as answers if they help and unmark them if they provide no help.

  

• No help has worked. Does someone have some working code in C that uses ReportEvent? Thanks.

• >Does someone have some working code in C that uses ReportEvent?

  The code from the URL you posted compiles without errors or
  warnings for me using VC++ 2008 Express.

  You need to supply more information about what you are
  doing and how you are doing it, if you want detailed
  help. You have made no mention of *exactly* how you
  have tried to build this example. From the IDE?
  From the command line? If IDE, using which Project
  Template? If from the command line, what was the
  actual and complete command used?

  — Wayne

• I have the required dll file and header file for the project.

  I used the 2003 PSDK to make those.

  I believe in order to test if it works would require changing the path to that dll file.

  I am willing to reinstall VC Express if I know that the program will actually work.

  I could upload those files in order to assist in any way.

  Could you do that for me?

  Maybe a screen shot of the results?

  Thanks,

  Andy

• I am at this point in my project.

  Where is the Win32 App Wizard?

  1. In the Win32 Application Wizard , click Application Settings to reveal options for Application type. Under
     Additional Options , select Empty Project and then click
     Finish .

  2. Further on down is this.

  3. Can I go straight to making the executable?

  Can I stop the autoformatting for my replies?

  Thanks.

  1. To build and examine the program

     1. On the Build menu, click Build Solution .

        The Output window displays information about the compilation progress, for example, the location of the build log and a message that states the build status.

     2. On the Debug menu, click Start without Debugging .

        If you used the sample program, a command window is displayed and shows whether certain integers are found in the set.

• Hello Raleigh77,

  If you compiling from command line, just add /entry:wmain

  Regards,

  Andrew

• Thanks Andrew.

  I have used Visual C++ only about 10 times.

  I will look at the help section for command line and see what is involved.

  Andy

• Clicked on Building on the Command Line and got:

• Walkthrough:  Compiling a Native C++ Program on the Command Line (C++)

• Thanks, seeing some good progress.

  Andy

  report_event.cpp
  C:Program FilesMicrosoft SDKsWindowsv6.0Aincludeprovider.h(25) : error C2470: ‘Provider’ : looks like a function definition, but there is no parameter list; skipping apparent body
  report_event.cpp(38) : error C2065: ‘UI_CATEGORY’ : undeclared identifier
  report_event.cpp(38) : error C2065: ‘MSG_INVALID_COMMAND’ : undeclared identifier
  report_event.cpp(40) : error C2065: ‘MSG_INVALID_COMMAND’ : undeclared identifier
  report_event.cpp(46) : error C2065: ‘DATABASE_CATEGORY’ : undeclared identifier
  report_event.cpp(46) : error C2065: ‘MSG_BAD_FILE_CONTENTS’ : undeclared identifier
  report_event.cpp(48) : error C2065: ‘MSG_BAD_FILE_CONTENTS’ : undeclared identifier
  report_event.cpp(55) : error C2065: ‘NETWORK_CATEGORY’ : undeclared identifier
  report_event.cpp(55) : error C2065: ‘MSG_RETRIES’ : undeclared identifier
  report_event.cpp(57) : error C2065: ‘MSG_RETRIES’ : undeclared identifier
  report_event.cpp(64) : error C2065: ‘UI_CATEGORY’ : undeclared identifier
  report_event.cpp(64) : error C2065: ‘MSG_COMPUTE_CONVERSION’ : undeclared identifier
  report_event.cpp(66) : error C2065: ‘MSG_COMPUTE_CONVERSION’ : undeclared identifier

• C:Program FilesMicrosoft SDKsWindowsv6.0Aincludeprovider.h(25) : error C2470: ‘Provider’ : looks like a function definition, but there is no parameter list; skipping apparent body

  Are we supposed to guess what line 25 of provider.h contains?

  — Wayne

•  // MyEventProvider.mc
   // This is the header section.
   // The following are the categories of events.
  //
  //  Values are 32 bit values layed out as follows:
  //
  //   3 3 2 2 2 2 2 2 2 2 2 2 1 1 1 1 1 1 1 1 1 1
  //   1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0
  //  +—+-+-+————————+——————————-+
  //  |Sev|C|R|     Facility          |               Code           
  |
  //  +—+-+-+————————+——————————-+
  //
  //  where
  //
  //      Sev — is the severity code
  //
  //          00 — Success
  //          01 — Informational
  //          10 — Warning
  //          11 — Error
  //
  //      C — is the Customer code flag
  //
  //      R — is a reserved bit
  //
  //      Facility — is the facility code
  //
  //      Code — is the facility’s status code
  //
  //
  // Define the facility codes
  //
  #define FACILITY_SYSTEM                  0x0
  #define FACILITY_STUBS                   0x3
  #define FACILITY_RUNTIME                 0x2
  #define FACILITY_IO_ERROR_CODE           0x4

  //
  // Define the severity codes
  //
  #define STATUS_SEVERITY_WARNING          0x2
  #define STATUS_SEVERITY_SUCCESS          0x0
  #define STATUS_SEVERITY_INFORMATIONAL    0x1
  #define STATUS_SEVERITY_ERROR            0x3

  //
  // MessageId: NETWORK_CATEGORY
  //
  // MessageText:
  //
  //  Network Events
  //
  #define NETWORK_CATEGORY                 ((WORD)0x00000001L)

  //
  // MessageId: DATABASE_CATEGORY
  //
  // MessageText:
  //
  //  Database Events
  //
  #define DATABASE_CATEGORY                ((WORD)0x00000002L)

  //
  // MessageId: UI_CATEGORY
  //
  // MessageText:
  //
  //  UI Events
  //
  #define UI_CATEGORY                      ((WORD)0x00000003L)

   // The following are the message definitions.
  //
  // MessageId: MSG_INVALID_COMMAND
  //
  // MessageText:
  //
  //  The command is not valid.
  //
  #define MSG_INVALID_COMMAND              ((DWORD)0xC0020100L)

  //
  // MessageId: MSG_BAD_FILE_CONTENTS
  //
  // MessageText:
  //
  //  File %1 contains content that is not valid.
  //
  #define MSG_BAD_FILE_CONTENTS            ((DWORD)0xC0000101L)

  //
  // MessageId: MSG_RETRIES
  //
  // MessageText:
  //
  //  There have been %1 retries with %2 success! Disconnect from
  //  the server and try again later.
  //
  #define MSG_RETRIES                      ((DWORD)0x80000102L)

  //
  // MessageId: MSG_COMPUTE_CONVERSION
  //
  // MessageText:
  //
  //  %1 %%4096 = %2 %%4097.
  //
  #define MSG_COMPUTE_CONVERSION           ((DWORD)0x40000103L)

   // The following are the parameter strings */
  //
  // MessageId: QUARTS_UNITS
  //
  // MessageText:
  //
  //  quarts%0
  //
  #define QUARTS_UNITS                     ((DWORD)0x00001000L)

  //
  // MessageId: GALLONS_UNITS
  //
  // MessageText:
  //
  //  gallons%0
  //
  #define GALLONS_UNITS                    ((DWORD)0x00001001L)

• <sigh> Are we supposed to guess which line generated the error?

  — Wayne

• If you can’t help me without criticizing me, then I can do without your «Help.»

  Andy

• Raleigh77 wrote:

  >

  >Thanks, seeing some good progress.

  >

  >Andy

  >

  >report_event.cpp

  >C:Program FilesMicrosoft SDKsWindowsv6.0Aincludeprovider.h(25) : error C2470: ‘Provider’ : looks like a function definition, but there is no parameter list; skipping apparent body

  >report_event.cpp(38) : error C2065: ‘UI_CATEGORY’ : undeclared identifier

  Are you including <windows.h> as your first include? The word before

  «Provider» in provider.h is POLARITY, which is defined in <polarity.h>,

  which should have been included, if you did things in the proper order.

  —

  Tim Roberts, timr@probo.com

  Providenza & Boekelheide, Inc.

  ---

  Tim Roberts, DDK MVP

• Thanks Tim.

  There is no reference to Polarity in any of my sources.

  I am using everything at the website that was provided.

  I will have to check but I believe that windows.h is in the source code.

  I assume that VB C++ knows what to do and that it was included in the package

  that I downloaded.

  Andy

• chocolatemint77581 wrote:

  >

  >There is no reference to Polarity in any of my sources.

  Yes, I know that. There are thousands and thousands of standard API

  include files, and those files depend greatly on one another, and on a

  particular ordering. Somehow, you have caused a standard file to be

  included without one of the files it depends on.

  That can happen if you #include a specific file by name without including

  <windows.h> first.

  >I am using everything at the website that was provided.

  >

  >I will have to check but I believe that windows.h is in the source code.

  >

  >I assume that VB C++ knows what to do and that it was included in the package

  >that I downloaded.

  There are rules to be followed to use these APIs. It’s a little dangerous

  to start compiling code without understanding what it does.

  —

  Tim Roberts, timr@probo.com

  Providenza & Boekelheide, Inc.

  ---

  Tim Roberts, DDK MVP

• http://msdn.microsoft.com/en-us/library/aa363677%28v=vs.85%29.aspx

  The source came from above, and as you can see, it is/was from Microsoft.

  The following example shows how to use the
  NotifyChangeEventLog function to receive notification when an event is logged.

  For the future, I will consider the possibility that any code, may be incomplete.

  But I did learn a lot from the process. 🙂

  Take care,

                   Andy

• chocolatemint77581 wrote:

  >

  >

  >The source came from above, and as you can see, it is/was from Microsoft.

  >

  >The following example shows how to use the NotifyChangeEventLog function to receive notification when an event is logged.

  >

  >For the future, I will consider the possibility that any code, may be incomplete.

  I don’t see how you get that. I just cut-and-pasted that text into a file

  called x.cpp, then did:

  cl x.cpp

  and it compiled and linked without any further ado.

  Still, if you have achieved success, that’s what matters.

  —

  Tim Roberts, timr@probo.com

  Providenza & Boekelheide, Inc.

  ---

  Tim Roberts, DDK MVP

• #define PROVIDER_NAME L"MyEventProvider"
  
  #define RESOURCE_DLL L"<path>\Provider.dll"

  But did your .exe run correctly ?

  If it did, you will have an event at the end of a specified event log.

  ( ReportEvent function writes an entry at the end of the specified event log.)

  I have some other questions for you.

  For the program to work, it needs a path to the dll.

  Did you change <path> to the actual path?

  Did you make provider.dll ?

  And no, I did not achieve sucess.

  Take care,

                  Andy

• Hello people,

  I have this problem in VS2010 10.0.30319.1 when i use template. if i put:

  template <typename T>

  int main(){

  return 0;

  }

  i will get this LNK1561 error…

  • Edited by
    Le10sn
    Saturday, October 13, 2012 9:52 PM

• Le10sn wrote:

  I have this problem in VS2010 10.0.30319.1 when i use template. if i  put:

  template <typename T>

  int main(){

  return 0;

  }

  i will get this LNK1561 error…

  main() function cannot be a template. Think about it: main() is called  by the operating system — how is the OS supposed to know which type to  use for T?

  ---

  Igor Tandetnik

  • Proposed as answer by
    madhudskumar
    Friday, July 18, 2014 4:38 AM
  • Unproposed as answer by
    madhudskumar
    Friday, July 18, 2014 4:38 AM

• Remove the void from the parameters of the main()

  it worked for me