Ask: the issue of releasing memory

iameinstein

Ask: the issue of releasing memory

Hello everyone, I need to open up a memory buffer in my program. After I open it up and use it, I want to release this memory buffer after closing the device and use the following code:
        if (pData!=NULL) //pData is the memory buffer I developed and used
        {
            delete pData;
        }
        pData=NULL;
When this code is not added, the program is normal, but after adding it, the compilation is passed, the link is passed, and a dialog box pops up as soon as the program is run:

Debug Assertion Failed!
Program:D:\test.exe
File:dbgheap.c
Line: 1011

Expression :_CrtIsValidHeapPointer (pUserData)

For information on how........

Terminate Retry Ignore


This is the first time I have encountered such a problem. I don't know how it happened. Please help. Thank you

shaziahlx

Pointer is invalid ................
Take the code at the time of the application

爱德华德

Change it to look like the following. In addition, can you guarantee that the memory is valid when pData != NULL?

if (pData!=NULL) //pData is the memory buffer I developed and used
{
   delete []pData;
}
pData=NULL;

iameinstein

Okay, the code is as follows:

void CAd65_testDlg::OnOpenDevice()
{
    // TODO: Add your control notification handler code here
   
    hDevice=Fmad_OpenDevice(0);
    if(hDevice!=INVALID_HANDLE_VALUE)
    {
      m_StatusDisplay.Format("Open successfully!\n");
      UpdateData(FALSE);
         
        GetDlgItem(IDC_OpenDevice)->EnableWindow(TRUE);
        GetDlgItem(IDC_StartSample)->EnableWindow(TRUE);
        GetDlgItem(IDC_CloseDevice)->EnableWindow(TRUE);
        UpdateData(FALSE);

   
    }
    else
    {
    m_StatusDisplay.Format("Failed to open!\n");
      UpdateData(FALSE);
    }
}



//------------------------------------------------ ---------------------------------//

void CAd65_testDlg::OnStartSample()
{
    // TODO: Add your control notification handler code here
    BOOL bStatus=FALSE;

    PULONG pData=new ULONG[786432]; //Apply for memory! ! ! ! ! ! ! ! ! ! !
    memset(pData,0,3145728); //clear all to 0
    int n = 0;


  bStatus=Fmad_WriteN(hDevice, 20);


  bStatus = Fmad_WriteUserParameter(hDevice, 62, 255);

                  
  bStatus = Fmad_SelClk(hDevice, FALSE);

               
  bStatus = Fmad_SetSample(hDevice, 0x3);


   
  bStatus = Fmad_StartSample(hDevice);


  bStatus = Fmad_WriteTrigger(hDevice);
  

    DWORD begin = 0;
    DWORD end = 0;
   
  
begin = GetTickCount();
cycle: while (!Fmad_DataReady(hDevice))
    {
    }
         
    if((n==0)||(n%2==0))
    {
    bStatus=Fmad_GetTrigData(hDevice,pData+(n*0x2000),0x4000*2,0x0);
           n++;
    }
    else
    {
    bStatus=Fmad_GetTrigData(hDevice,pData+(n*0x2000),0x4000*2,0x8000);
    n++;
    }

         if(n <64)
    {
    goto cycle;
    }

    bStatus = false;
    bStatus = Fmad_SetSample(hDevice, 0x0);
   
    end = GetTickCount();
    DWORD timeUse = end-begin; //The number of milliseconds used for execution
            
    static char BASED_CODE szFilter[] = "Binary file (*.dat)|*.dat||";
    CString msg;
    CString sFile;
    CFileDialog dlgFile(FALSE,NULL,NULL,OFN_HIDEREADONLY | OFN_OVERWRITEPROMPT,\
                        szFilter,NULL);
    dlgFile.m_ofn.lpstrTitle="Save";
    dlgFile.DoModal();
    sFile=dlgFile.GetFileName();
    if(!sFile.IsEmpty())
    {
        int n=sFile.Find(".dat");
        if(n<0)
            sFile=sFile+".dat";
        CFile file;
        if(!file.Open(sFile,CFile::modeCreate|CFile::modeWrite))
        {
            msg.Format("Can't not open the file %s.",sFile);
            AfxMessageBox(msg);
            return;
        }

     file.Write(pData,3145728);
     file.Close();
/*
     if (pData!=NULL) //pData is the memory buffer I opened and used, as long as it is added, the program will pop up a dialog box
        {
          delete []pData;
        }
*/
}
}

void CAd65_testDlg::OnCloseDevice()
{
    // TODO: Add your control notification handler code here
          hDevice = Fmad_CloseDevice(hDevice);
            if(hDevice==INVALID_HANDLE_VALUE)
    {
        GetDlgItem(IDC_OpenDevice)->EnableWindow(TRUE);
        GetDlgItem(IDC_StartSample)->EnableWindow(FALSE);
        GetDlgItem(IDC_CloseDevice)->EnableWindow(FALSE);
    }
    else
        AfxMessageBox("Can't Close Device !");
}

shaziahlx

As said on the second floor

delete []pData;

爱德华德

PULONG pData=new ULONG[786432]; //Apply for memory! ! ! ! ! ! ! ! ! ! !
memset(pData,0,3145728); //Clear all 0 to 786432

I was wrong above

shaziahlx

memset(pData,0,3145728);
-----------------------
Is this right

爱德华德

delete [](ULONG*)pData;

iameinstein

Change it to this: delete [](ULONG*)pData;
Or not
memset(pData,0,3145728); Yes, it is to clear the byte to 0

爱德华德

You block first

file.Write(pData,3145728);
file.Close();

Take a look at delete
I seem to have encountered this problem before, and I can’t remember why for a while