GDB breakpoints with multiple conditions on non-native types

Question

I'm debugging a C/C++ program where I want to set a single break point with a condition depending on multiple variables.

break foo.cpp:60 if (bar == 3 && i == 5)

This doesn't seem to work, as it stops whenever it hits foo.cpp:60 instead of whenever both of the conditions match (it doesn't even match one of the conditions). Is there an easy way to do what I'm trying to achieve?

Edit: bar and i are not native C types, they are strongly typed.

break foo.cpp:60 if ((A) bar == 3 && (B) i == 5)

Take a look at the GDB documentation. Here is a location for the _[quickStartGuide](http://teaching.csse.uwa.edu.au/units/CITS2230/resources/gdb-intro.html#breakpoints)_. — ryyker, Jul 24 '17 at 18:48
"they are strongly typed" -- this tells us *nothing*. You need to provide a https://stackoverflow.com/help/mcve if you want help. — Employed Russian, Jul 25 '17 at 01:24
When it incorrectly stops at line 60, what do `p bar`, `p (A) bar`, `p i`, and `p (B) i` show? — Mark Plotnick, Jul 25 '17 at 14:13
Related: https://stackoverflow.com/questions/7423577/how-to-compare-a-stored-string-variable-in-gdb/7424716 — Ciro Santilli OurBigBook.com, Apr 16 '20 at 15:23

ryyker · Answer 1 · 2017-07-24T19:17:27.980

1

Resolve your condition statement and place its result into its own BOOL variable, then set your break point statement to evaluate the single variable. This puts the form squarely in-line with examples shown in the GDB. documentation:

eg:

BOOL x = FALSE;

x = ((bar == 3) && (i == 5));

(gdb)   break foo.cpp:60 if x

edited Jul 24 '17 at 19:17

answered Jul 24 '17 at 18:51

ryyker

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Unfortunately it still doesn't work, gdb returns the error 'No symbol "operator==" in current context.' I should mention that bar and i are not native c types (they are defined strong types). Is there a form of casting I should do? i.e. if ((bar == (A) 3) && (i == (B) 5)? – ginginsha Jul 24 '17 at 18:54
@ginginsha - Provide more information about how exactly these variables are created/typed. Edit your original post if needed so all will see it. – ryyker Jul 24 '17 at 19:23

score 0 · Answer 2 · answered Jan 18 '18 at 18:22

0

This works for me.

(gdb) b dump_route_info if (strncmp(route->rt_key.prefix, "192.168.0.2", 15) == 0) && route->rt_key.mask == 32

answered Jan 18 '18 at 18:22

Abhishek Sagar

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GDB breakpoints with multiple conditions on non-native types

2 Answers2

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