I can debug Python code using
ddd -pydb prog.py
I found out how to debug the C++ part while running python. (while reading Python book..).
First you run the python program which includes C++ programs. At the start of the python program, use raw_input() to make the program wait for you input. But just before that do
print os.getpid() (of course you should have imported os package). When you run the python program, it will have printed the pid of the python program you are running and will be waiting for your keyboard input.
python stop code :
import os def w1(str): print (str) wait = raw_input() return print os.getpid() w1('starting main..press a key')
27352 starting main..press a key
Or, you can use import pdb, pdb.set_trace() as comment below.(thanks @AndyG)
Now, suppose the C++ shared library is _caffe.so (which is my case. This _caffe.so library has all the C++ codes and boost python wrapper functions). 27352 is the pid. Then in another shell start gdb like
gdb caffe-fast-rcnn/python/caffe/_caffe.so 27352
or if you want to use graphical debugging using like DDD, do
ddd caffe-fast-rcnn/python/caffe/_caffe.so 27352
Then you'll see gdb starts and wait with prompt. The python program is interrupted by gdb and waits in stopped mode (it was waiting for your key input but now it's really in stopeed mode, and it needs gdb continue command from the second debugger to proceed with the key waiting).
Now you can give break point command in gdb like
and you can see message like
Breakpoint 1 at 0x7f2cccf70397: file src/caffe/solver.cpp, line 226. (2 locations)
When you give
continue command in the second gdb window(that was holding the program), the python code runs again. Of course you should give a key input in the first gdb window to make it proceed.
Now at least you can debug the C++ code while running python program(that's what I wanted to do)!
I later checked if I can do python and C++ debugging at the same time and it works. You start the debugger(DDD) like
ddd -pydb prog1.py options.. and attach another DDD using method explained above. Now you can set breakpoints for python and C++ and using other debug functions in each window(I wish I had known this a couple of months earlier.. I should have helped tons.).
EDIT : to get the pid, you can do
ps -aux | grep python instead. This pid is the next of ddd's pid.