这为什么会出错？对共享内存设置为0

[ForgetTomorrow]

共享内存大小设成1024时没问题，设置成10*1024时在meset这里报错，为什么啊？

[ForgetTomorrow]

引用 2 楼 zgl7903 的回复:

1按系统页面的整数倍来处理， 2 返回的句柄 & 缓冲区指针要先判断是否有效

SYSTEM_INFO sysInfo;
GetNativeSystemInfo(&sysInfo);
int BUF_SIZE = 102400 * sysInfo.dwPageSize;

到4096就崩溃

[ForgetTomorrow]

windows系统有对共享内存大小限制吗？我这只能设置到1kb，大于1kb访问错误

[zgl7903]

int Test()
{
  int iErr = 0;

  TCHAR szName[]=TEXT("Global\\MyFileMappingObject");
  
  SYSTEM_INFO sysInfo;
  GetNativeSystemInfo(&sysInfo);
  int BUF_SIZE = 102400 * sysInfo.dwPageSize;

  HANDLE hMapFile = NULL;
  LPVOID pBuf = NULL;

  do
  {
    hMapFile = CreateFileMapping(
      INVALID_HANDLE_VALUE,    // use paging file
      NULL,                    // default security 
      PAGE_READWRITE,          // read/write access
      0,                       // max. object size 
      BUF_SIZE,                // buffer size  
      szName);                 // name of mapping object

    if (hMapFile != NULL) 
    {
      printf("CreateFileMapping %d (bytes) ok\n", BUF_SIZE);
    }
    else
    { 
      iErr = GetLastError();
      printf("Could not create file mapping object (%d).\n", iErr);
      break;
    }

    pBuf = MapViewOfFile(hMapFile,   // handle to map object
      FILE_MAP_ALL_ACCESS, // read/write permission
      0, 0, 0);           

    if (pBuf == NULL) 
    { 
      iErr = GetLastError();
      printf("Could not map view of file (%d).\n", iErr); 
      break;
    }

    for(LONG i=0; i<BUF_SIZE; i++)
    {
      ((BYTE*)pBuf)[i] = (BYTE)i;
    }

    printf("Write done\n");

    _getch();

  }while(0);

  if(pBuf != NULL)
  {
    UnmapViewOfFile(pBuf);
    pBuf = NULL;
  }

  if(hMapFile != NULL)
  {
    CloseHandle(hMapFile);
    hMapFile = NULL;
  }

  return iErr;
}

[ForgetTomorrow]

引用 楼主 ForgetTomorrow 的回复:

共享内存大小设成1024时没问题，设置成10*1024时在meset这里报错，为什么啊？

调试发现最多只能4*1024大小，再大就不行了

[zgl7903]

1按系统页面的整数倍来处理， 2 返回的句柄 & 缓冲区指针要先判断是否有效 SYSTEM_INFO sysInfo; GetNativeSystemInfo(&sysInfo); int BUF_SIZE = 102400 * sysInfo.dwPageSize;