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Editorial Team
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Asked: 2026-05-16T05:18:49+00:00

An earlier question explained that on x86 the size of objects being watched is

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An earlier question explained that on x86 the size of objects being watched is limited by debug registers. As expected, I can “watch” a double variable. But I can’t watch a double datamember, for example,

watch pObject->dPrice

produces

Hardware watchpoint 1: pObject->dPrice

But when you try to continue execution, it says

Could not insert hardware breakpoints:
You may have requested too many hardware breakpoints/watchpoints.

even though this is the only breakpoint/watchpoint.

I’m curious why this is so, but more importantly is there a way around it? According to GDB documentation it may use software watchpoints if it can’t use hardware. In this case it makes no attempt to use a software watchpoint — is there a way to force it to do so?

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1 Answer

  1. Editorial Team

    Yes, you can:

    set can-use-hw-watchpoints 0

    From 5.1.2 Setting Watchpoints:

    You can force GDB to use only software watchpoints with the set can-use-hw-watchpoints 0 command. With this variable set to zero, GDB will never try to use hardware watchpoints, even if the underlying system supports them. (Note that hardware-assisted watchpoints that were set before setting can-use-hw-watchpoints to zero will still use the hardware mechanism of watching expression values.)

    set can-use-hw-watchpoints

        Set whether or not to use hardware watchpoints.

    show can-use-hw-watchpoints

        Show the current mode of using hardware watchpoints.

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