c - 内存分配错误 OpenCV cvReleaseMat

Question

CvMat* traindata=cvCreateMat(1000,36,CV_32FC1);

当我尝试使用释放此矩阵时cvReleaseMat(&trainData)

我发现任务管理器中的内存没有减少...相反，此发布命令对任务管理器中此应用程序的内存没有任何影响。

我的疑问是……是否也cvReleaseMat 释放了 CPU 中的内存？或者它只是让这个矩阵在未来变得不可见？

Answer 1

是cvReleaseMat的，确实释放了内存。任务管理器并不是真正查看 CvMat* 分配内存的工具。尽管如果您将矩阵做得更大，您可能会注意到它。该矩阵占用 1000 * 36 * 4 = 144000 字节。

您可以在 valgrind 分析的以下代码的输出中看到它：

CvMat* traindata = cvCreateMat(1000, 36, CV_32FC1);
//cvReleaseMat(&traindata);

相关的 valgrind 输出是：

==4967== HEAP SUMMARY:
==4967==     in use at exit: 144,108 bytes in 2 blocks
==4967==   total heap usage: 10 allocs, 8 frees, 144,772 bytes allocated
==4967== 
==4967== LEAK SUMMARY:
==4967==    definitely lost: 64 bytes in 1 blocks
==4967==    indirectly lost: 144,044 bytes in 1 blocks
==4967==      possibly lost: 0 bytes in 0 blocks
==4967==    still reachable: 0 bytes in 0 blocks
==4967==         suppressed: 0 bytes in 0 blocks

但如果你真的释放CvMat

CvMat* traindata = cvCreateMat(1000, 36, CV_32FC1);
cvReleaseMat(&traindata);

你得到这个输出，现在注意 valgrind 的输出：

==4957== HEAP SUMMARY:
==4957==     in use at exit: 0 bytes in 0 blocks
==4957==   total heap usage: 10 allocs, 10 frees, 144,772 bytes allocated
==4957== 
==4957== All heap blocks were freed -- no leaks are possible