这会泄漏内存吗？ 我该如何预防？

Question

I see that this question 's answer is really popular regarding how to print a cv::Mat image into an MFC application.

However, I was wondering if there is a memory leak there? or if there is none, how is that possible?

In specific, I'm wondering about the memset(bmih, 0, sizeof(*bmih)) part. Is it that MFC somehow manages the memory here? Can someone provide some information regarding this?

void COpenCVTestView::FillBitmapInfo(BITMAPINFO* bmi, int width, int height, int bpp, int origin) 
{ 
assert(bmi && width >= 0 && height >= 0 && (bpp == 8 || bpp == 24 || bpp == 32)); 

BITMAPINFOHEADER* bmih = &(bmi->bmiHeader); 
// this part shouldn't leak?
memset(bmih, 0, sizeof(*bmih)); 
bmih->biSize = sizeof(BITMAPINFOHEADER); 
bmih->biWidth = width; 
bmih->biHeight = origin ? abs(height) : -abs(height); 
bmih->biPlanes = 1; 
bmih->biBitCount = (unsigned short)bpp; 
bmih->biCompression = BI_RGB; 

if (bpp == 8) 
{ 
    RGBQUAD* palette = bmi->bmiColors; 

            for (int i = 0; i < 256; i++) 
    { 
        palette[i].rgbBlue = palette[i].rgbGreen = palette[i].rgbRed = (BYTE)i; 
        palette[i].rgbReserved = 0; 
    } 
} 
}

Answer 1

Where do you see a memory leak? There's no dynamic allocation, and no pointer manipulation. A memset coul cause a memory leak, if it overwrote a pointer to dynamically allocated memory, but there's no pointer in a BITMAPINFOHEADER , just integers.

Answer 2

The memset just fills the bmih object with zeros in this case. So there is no memory leak.

The FillBitmapInfo method is called with a pointer to a BITMAPINFO object that was previously allocated somewhere else. bmih is just a reference to the bmiHeader member of the BITMAPINFO struct. memset just assigns a value to the memory region referenced by bmih .

Answer 3

A memset() doesn't cause a memory leak. That just writes 0x00 bytes into part of the memory pointed to by bmi . There is not enough code here to determine whether any memory is leaked.