Error summary in Valgrind output?

Question

I have seen some of the post regarding valgrind but not single post helped me in understanding interpretation of valgrind output. I ran two programs with valgrind (Both having memory leaks)

Sample Output for Test 1

==20422== LEAK SUMMARY:
==20422== definitely lost: 448 bytes in 3 blocks
==20422== indirectly lost: 786,460 bytes in 1 blocks
==20422== possibly lost: 1,576,052 bytes in 46 blocks
==20422== still reachable: 1,077,107 bytes in 2,333 blocks
==20422== suppressed: 0 bytes in 0 blocks
==20422== Rerun with --leak-check=full to see details of leaked memory
==20422==
==20422== For counts of detected and suppressed errors, rerun with: -v
==20422== ERROR SUMMARY: 98307 errors from 5 contexts (suppressed: 2 from 2)
Killed

Output for Test 2

==20875== HEAP SUMMARY:
==20875== in use at exit: 1,059,198 bytes in 2,047 blocks
==20875== total heap usage: 3,019 allocs, 972 frees, 4,496,090 bytes allocated
==20875==
==20875== LEAK SUMMARY:
==20875== definitely lost: 328 bytes in 2 blocks
==20875== indirectly lost: 0 bytes in 0 blocks
==20875== possibly lost: 1,600 bytes in 5 blocks
==20875== still reachable: 1,057,270 bytes in 2,040 blocks
==20875== suppressed: 0 bytes in 0 blocks
==20875== Rerun with --leak-check=full to see details of leaked memory
==20875==
==20875== For counts of detected and suppressed errors, rerun with: -v
==20875== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 2 from 2)

If you look at the error summary, One output says there are errors and other says there are no errors (eventually both have leaks)

My question is - - what is counted as error in valgrind? (valgrind manual didn't helped me)

Answer 1

Memory leaks are not considered errors, they don't effect the logic of the program.

Errors are things such as invalid reads and writes.

Updated as result of comment: The invalid reads and writes in test 1 are for 5 different areas of memory which are accessed 98307 times.

Looking at the leaks, the large indirect losses in test 1 may indicated a linked data structure where only the root has been deleted.

The leaks in test 2 aren't too bad. As valgrind suggests rerun with --leak-check=full which should indicate which bit of code is causing the problem.

A full explanation of the errors can be found here