gdb: how to print the current line or find the current line number?

Solution 1:

The 'frame' command will give you what you are looking for. (This can be abbreviated just 'f'). Here is an example:

(gdb) frame
\#0  zmq::xsub_t::xrecv (this=0x617180, msg_=0x7ffff00008e0) at xsub.cpp:139
139         int rc = fq.recv (msg_);
(gdb)

Without an argument, 'frame' just tells you where you are at (with an argument it changes the frame). More information on the frame command can be found here.

Solution 2:

Command where or frame can be used. where command will give more info with the function name

Solution 3:

I do get the same information while debugging. Though not while I am checking the stacktrace. Most probably you would have used the optimization flag I think. Check this link - something related.

Try compiling with -g3 remove any optimization flag. Then it might work. HTH!