Friday, May 17, 2013

pdb and gdb conditional breakpoints

Use a debugger enough and you'll eventually be in a loop looking for a certain condition. And it's too tedious to walk through all iterations of the loop to get to the one you want. Enter conditional breakpoints. In GDB you'd use something like this (borrowed from here):
(gdb) br test.cpp:2
Breakpoint 1 at 0x1234: file test.cpp, line 2.
(gdb) cond 1 i==2147483648
(gdb) run
Or this for strings:
break test2.cpp:10 if strcmp(y,"hello") == 0
In the python debugger the syntax is a little different:
b(reak) ([file:]lineno | function) [, condition]
Like this:
(Pdb) break, somevalue=2

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