Failed to detect memory leak in Win32 mode when using OpenCV's imshow and waitKey

[zchrissirhcz]

Tested on VS2017 with Win32 and X64 mode. vld version is 2.6.0. VS2017 version is 15.9.27. X64 mode reports memory leak. Win32 mode doesn't report memory leak.

Reproduceable code: (What this code does is: read a text that contains image names, then read each rgb image, resize to 256x256, and show them in window, finally call a function that does contain an memory leak, and expect VLD report memory leaks):

#include <vld.h>

#include <stdio.h>
#include <stdlib.h>

#include <string>
#include <vector>
#include <opencv2/opencv.hpp>

void leak_test2()
{
    int len = 100;
    int size = len * sizeof(int);
    int* data = (int*)malloc(size);
    data[0] = 100;
    data[200] = 3;
}

static void read_txt_line_by_line(const char* path, std::vector<std::string>& image_paths)
{
    FILE* fin = fopen(path, "r");
    if (fin == NULL) {
        fprintf(stderr, "failed to open %s\n", path);
        exit(-1);
    }
    char line[1024];
    void* ret;
    while (true) {
        memset(line, 0, sizeof(line));
        ret = fgets(line, sizeof(line), fin);
        if (ret == NULL) break;
        if (line[strlen(line) - 1] == '\n' || line[strlen(line) - 1] == '\r') {
            line[strlen(line) - 1] = '\0';
        }
        if (line[strlen(line) - 1] == '\r' || line[strlen(line) - 1] == '\n') {
            line[strlen(line) - 1] = '\0';
        }
        //printf("%s\n", line);
        image_paths.push_back(line);
    }
    fclose(fin);
}

static void rgb_bgr_swap(unsigned char* data, int h, int w)
{
    int len = h * w * 3;
    for (int i = 0; i < len; i += 3) {
        unsigned char t = data[i];
        data[i] = data[i + 2];
        data[i + 2] = t;
    }
}

static void leak_test_()
{
    int h = 256; // height
    int w = 256; // width
    int c = 3;   // channel
    int len = h * w*c;
    size_t buf_size = len * sizeof(unsigned char);
    unsigned char* data = (unsigned char*)malloc(buf_size); // image buffer
    unsigned char* ptr = data;
    for (int i = 0; i < h; i++) {
        for (int j = 0; j < 256; j++) {
            *ptr++ = (unsigned char)j;    /* R */
            *ptr++ = (unsigned char)i;    /* G */
            *ptr++ = 128;                 /* B */
        }
    }

    rgb_bgr_swap(data, h, w);
    cv::Mat result(h, w, CV_8UC3, data);
    cv::imwrite("result.jpg", result);

    // [step2]
    //free(data);  //here, we make an memory leak
}

void leak_test_imshow()
{
    std::string data_dir = "E:/data/VOC2007";
    std::string im_dir = "E:/data/VOC2007/JPEGImages";
    std::string txt_pth = "E:/data/VOC2007/lite+.txt";

    std::vector<std::string> image_paths;
    read_txt_line_by_line(txt_pth.c_str(), image_paths);

    //cv::namedWindow("image");
    for (int i = 0; i < image_paths.size(); i++) {
        if (i > 10) break;
        image_paths[i] = im_dir + "/" + image_paths[i];
        printf("image_paths[i]=%s\n", image_paths[i].c_str());
        cv::Mat image = cv::imread(image_paths[i]);
        cv::resize(image, image, cv::Size(256, 256));
        cv::imshow("image", image);
        cv::waitKey(100);
    }

    leak_test_();

}

int main()
{
    printf("--- begin leak test\n");
    //leak_test2();
    leak_test_imshow();
    printf("--- end   leak test\n");

    return 0;
}

Running result:

[zchrissirhcz]

Figured out that Win32 mode still can give VLD output, by adding this line in the very last of main() function:

VLDReportLeaks();

[oneiric]

Since VLD can work, I will close this issue.