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Author Topic: Implicit limitation of breakpoints number ?  (Read 1513 times)

ruk1n

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Implicit limitation of breakpoints number ?
« on: June 08, 2017, 01:40:09 pm »
Hello,

The debugger seems to silently exit when I have more than 4 data/watch breakpoints enabled. By _silently exit_, I mean it does not debug any longer.

I am using Lazarus 1.6.4 + fpc 302 under windows 7 and 10 (64bits). And I have carefully reviewed debugger's topic on the wiki.

Any clue ?
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ruk1n

Martin_fr

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Re: Implicit limitation of breakpoints number ?
« Reply #1 on: June 08, 2017, 02:56:19 pm »
It is possible that there are limits in gdb (the IDE uses gdb as debugger).
I dont know if/where this is documented for gdb.

This may also depend on your hardware / your CPU.

There are 2 ways to do watchpoints

1) hardware watch points. those are a feature of your CPU. And the number of those is limited by your CPU.

2) Software watchpoints. (if supported by gdb for your platform / and not sure if the IDE even tells gdb to try them)
Software watchpoints are really slow. It basically means to single step the app, and check the memory after each step. This would really slow down execution of your app.

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In any case, if the breakpoint can not be set, there should be an error, and you should get the option to continue without that breakpoint.
But I haven't tested that, and I don't know what gdb will report in this case.


 

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