Break when a register has an specific value?

Question

Any way to make Windbg to break when a specific value is assigned to the eax register? I know one of the functions in my program is returning an specific error, it would be very fast to find the guilty this way.

Answer 1

You can set a breakpoint on all your suspect functions and then check the eax register value like so:

bp myAddress ".if (@retreg == dodgyVal) {walk the stack and do other cool stuff} .else {gc}"

See conditional breakpoints and also pseudo-register syntax for available register values