fix bug, undefined behavior that resulted in segfault #4
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declaring external int variable as a long results in undefined GCC behavior. This resulted in a segmentation fault when using this variable for a comparison.
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Declaring external int variable as a long results in undefined GCC behavior. This resulted in a segmentation fault when using this variable for a comparison.
Details: size variables are defined as ints:
https://github.com/trec-health-misinfo/Trec_eval_extension/blob/2d4e34c2b4a5d6f0f049ff9296f9b6060c39ba2e/Trec_eval_extension/measures.c#L184
but they were imported as longs:
https://github.com/trec-health-misinfo/Trec_eval_extension/blob/2d4e34c2b4a5d6f0f049ff9296f9b6060c39ba2e/Trec_eval_extension/trec_eval.c#L127
This is undefined behavior. GCC doesn't warn about it and nor does Valgrind, so it was a difficult bug to find. The bug resulted in non-ending loops like the one in
https://github.com/trec-health-misinfo/Trec_eval_extension/blob/2d4e34c2b4a5d6f0f049ff9296f9b6060c39ba2e/Trec_eval_extension/trec_eval.c#L349
which in turn resulted in a segmentation fault.
This was already pointed out in #2 , but the root cause of the bug was not found. Looks like older versions of GCC dealt "in the right way" with this undefined behavior.