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c++gdbbacktracebad-alloc

c++ bad_alloc, but it disappear in gdb

I have a big project, compiles fine, but sometimes when I run in terminal(sometimes not) 

./run

it gives bad_alloc exception, so i think it might be helpful to backtrace using gdb, so I do

gdb ./run
run

and it weirdly exit normally, nothing wrong shows up, even though I tried a lot of times. Has someone met similar issues before?

Solution

  • See this answer for what may be different "inside" vs. "outside" of GDB, and what to do about it.

    If you can enable core dumps (ulimit -c unlimited), that should give you another way to get the stack trace.

    In my experience, most bad_allocs result from one of two root causes:

    1. Uninitialized size:

      int size; if (something) { // assign to size here } std::vector v(size); // Oops: size may be unintialized.

    2. Arithmetic underflow:

      std::vector v(other_vector.size() - 20);

      Here, if other_vector.size() < 20, you'll get humongous value.