CODEWITHSUNDEEP
c++linuxgdb
razorf9
razorf9

Reputation: 11

Understanding gdb output

I am trying to use the push_back function for a vector in c++. I am getting a seg fault and when I ran the gdb to find the exact reason.

I get the following.

$1={px = 0xbfffe9c4, pn = { pi_ = 0x8049c0b}}

I do not have much experience with gdb and cannot find anything related to this specific issue online.

Upvotes: 1

Views: 692

Answers (1)

jxh
jxh

Reputation: 70402

My magic ball tells me you crashed while dereferencing a shared_ptr. Follow the px member, since that is the actual pointer value of interest to you. For example, you can try:

print $1.px

and if the pointer points to a valid memory area:

print *$1.px

The gdb debugger will provide you with a lot of information, but some of the more useful things: backtrace, up, down, info locals, and if you are multi-threaded, thread apply all backtrace. If you are debugging live, then of course you will need breakpoint, next, step and continue. You should be able to use gdb's help for more information, and the gdb manual is readily available online.

Upvotes: 3

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