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

Question

list commands prints a set of lines  but I need one single line  where I am and where an error has probably occurred

User · Accepted Answer

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!

User · Answer

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

User · Answer

Keep in mind that gdb is a powerful command -capable of low level instructions- so is tied to assembly concepts   What you are looking for is called de instruction pointer  i e      The instruction pointer register points to the memory address which the processor will next attempt to execute  The instruction pointer is called ip in 16-bit mode  eip in 32-bit mode and rip in 64-bit mode    more detail here  all registers available on gdb execution can be shown with    gdb  info registers   with it you can find which mode your program is running  looking which of these registers exist   then  here using most common register rip nowadays  replace with eip or very rarely ip if needed     gdb info line   rip   will show you line number and file source   gdb  list   rip   will show you that line with a few before and after  but probably    gdb  frame   should be enough in many cases

User · Answer

All the answers above are correct  What I prefer is to use tui mode  ctrl X A or  tui enable   which shows your location and the function in a separate window which is very helpful for the users  Hope that helps too

User · Answer

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

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

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