Why does Eclipse CDT ignore breakpoints?

问题:

My problem is that I set some breakpoints in my code and some of them aren't working. In some places it complains about "Unresolved Breakpoint".

Does anyone have any clue why this is happening? I am using gdb, by the way.

EDIT: Yes, of course is compiled with debug information. It only happens at some classes or points in the code. And I am pretty sure that that part of the code is reached because I can reach it stepping

EDIT: The solution from Richard doesn't work; thanks anyway. I am compiling in Debug, without any optimization.

回答1:

Could it be that you are trying to set breakpoints in a shared library that has not been loaded yet. That won't work until the library has loaded. Newer gdb allow to set deferred breakpoints, but that may not (yet) be supported by CDT. A workaround is to set a breakpoint in a place that is available from the beginning that will be reached when the shared library in question is already loaded. Then set the other breakpoint in the shared library. Now it should work. It's a bit more tedious, but usually works.

From the GDB documentation:

For a pending breakpoint whose address is not yet known, this field will contain 'PENDING'. Such breakpoint won't fire until a shared library that has the symbol or line referred by breakpoint is loaded.

回答2:

I have found that sometimes switching the referred Process Launcher from "GDB (DSF) Create Process Launcher" to "Standard Create Process Launcher" has fixed this problem for me. Other times, just deleting all breakpoints and restarting Eclipse does the trick.

回答3:

"Unresolved Breakpoint" just means that GDB did not find code location corresponding to the file and line on which you attempted to set a breakpoint.

Are you trying to stop in a constructor?

If so, you are likely seeing this cently fixed GCC bug.

回答4:

Sometimes optimizations will cause breakpoints to be skipped as well. Make sure you're compiling with -O0

回答5:

I have found that using F8 (resume) doesn't stop at my breakpoints. But, if I have Stop On Startup : main set then then step over my code (F5/F6) then my breakpoints are hit. I don't have any special compiler options other than -g or -g3. Hope that help...

回答6:

Make sure the breakpoint type is correct. For C/C++ it's a tiny blue dot. If it looks like anything else, chances are the breakpoint type is incorrect. I would try to close the file, right click on it -> open with -> C/C++ Editor. This worked for me.

回答7:

If other answers here didn't solve your problem, it is possible you are having the same problem I had (which was the result of having an outdated version of GDB). This is likely the case for anyone using GDB on Mac.

See my question and answer here:

GDB does not break on some lines of code when using multiple source files

回答8:

Do you place a breakpoint in a template class/function? I've met the same problem: I can step through the code of templates but breakpoints do not work. I guess eclipse does not understand that it has to place breakpoints in all instantiations of that class:

template <typename T>
int doit(T a) {
 return a.do(); // <-- breakpoint here
}
...
A a;
cout << doit(a);

I think it will wait for doit(...) and never for doit(...). At lease gdb itself stops on the breakpoint if I set it to the function: 'doit'.

回答9:

I had a similar issue with GDB. It seems that it was caused by identical source code filesnames even if they have different paths. I renamed the duplicates and GDB worked just fine after that.

Silviu

回答10:

i had the same problem,

1.- Removed the breakpoints. 
2.- Restart eclipse 
3.- Clean the project by using project -> clean 
4.- Add again the breakpoints and start your debugging.

This solved my issue.

回答11:

IF you are using GDB as a debugger, make sure you are using both flags: -g and -ggdb

You can either edit the make file directly, FCFLAGS = -g -ggdb (some other flags you might have)

or go to Debug Configuration (It's in the menu that drops down when you click on the little arrow besides the bug icon.) Select the project you are debugging, and click on the debugger tab. Check you are using gdb, and add the flags here.