Question

Is it possible in gdb to go to a line before the currently executing line.
e.g:

void my_fun( somePtrType** arr,int start,int end)
{
 // arr is an array of pointers to somePtrType
  //line a
 ... some assignments
 swap(&arr[ind1] , &arr[ind2] ) ;
 //line b (current line )
}

I am at line b currently and can examine the arr values there but I want to go back to line a and examine the contents of arr at that time.

I think it might not be possible because a debugger can run a code in slow motion,but can’t make it execute backwards.
Any more insights..

Answer 1

Yes! With the new version 7.0 gdb, you can do exactly that!

The command would be “reverse-step“, or “reverse-next“.

You can get gdb-7.0 from http://ftp.gnu.org:/pub/gnu/gdb

If you run into the error: Target child does not support this command. then try adding target record at the beginning of execution, after starting run.

Edit: Since GDB 7.6 target record is deprecated, use target record-full instead.