setting a breakpoint when variable reaches specific value

Is there anyway to set a breakpoint when a vari开发者_JS百科able reaches a specific value in GDB? For example, a variable take these values: 1 4 8 10 3 2 9 13 11 and I want to set a breakpoint when this variable reaches 9.

Yes, set breakpoint with condition.

break ... if value==9

You can use watchpoints for this.

watch n > 9

...should break when the Boolean expression n > 9 changes; that is, whenever n goes from smaller than or equal to 9 to bigger than 9 or vice-versa.