watchpoint

问题 I want to set a watchpoint (break on hardware write) temporarily in my C++ program to find memory corruption. I've seen all the ways to do it manually through gdb, but I would like to actually set the watchpoint via some method in my code so I don't have to break into gdb, find out the address, set the watchpoint and then continue. Something like: #define SET_WATCHPOINT(addr) asm ("set break on hardware write %addr") 回答1: Set hardware watchpoint from child process. #include <signal.h>

问题 I want to set a watchpoint (break on hardware write) temporarily in my C++ program to find memory corruption. I've seen all the ways to do it manually through gdb, but I would like to actually set the watchpoint via some method in my code so I don't have to break into gdb, find out the address, set the watchpoint and then continue. Something like: #define SET_WATCHPOINT(addr) asm ("set break on hardware write %addr") 回答1: Set hardware watchpoint from child process. #include <signal.h>

问题 what is the difference between break *main and break main() in essence? for example: #include <iostream> using namespace std; int main() { int x=30; int y=40; x=y; return 0; } when I use break *main and watch x , it is this: (gdb) b *main Breakpoint 1 at 0x400674: file aa.cpp, line 4. (gdb) r Starting program: /root/dd/aa.out Breakpoint 1, main () at aa.cpp:4 4 { (gdb) n 5 int x=30; (gdb) watch x Hardware watchpoint 2: x (gdb) c Continuing. Hardware watchpoint 2: x Old value = 0 New value =

问题 Watchpoints on function-local variables usually get removed upon the function return, with a message «Watchpoint 7 deleted because the program has left the block in». Illustration: struct mystruct{ int a, b, c; }; void MyFunc(){ mystruct obj; obj.a = 2; } int main(){ MyFunc(); } gdb session example (gdb) b 7 Breakpoint 1 at 0x4004f1: file /tmp/test2.cpp, line 7. (gdb) r Starting program: /tmp/test2 Breakpoint 1, MyFunc () at /tmp/test2.cpp:7 7 obj.a = 2; (gdb) wa obj Hardware watchpoint 2:

问题 You can easily set a watchpoint in XCode by following these steps (btw if there is a simpler way, I'd like to know it...): - Run your program - Set a breakpoint in the code where your variable is used - when reaching breakpoint, use a right click on the variable and select 'Watch "nameOfTheVariable"' - Continue execution. The only problem is that execution will stop every time the variable value changes. I would like XCode to continue the execution without stopping, i.e. merely display the

问题 How do GDB watchpoints work? Can similar functionality be implemented to harness byte level access at defined locations? 回答1: I believe gdb uses the MMU so that the memory pages containing watched address ranges are marked as protected - then when an exception occurs for a write to a protected pages gdb handles the exception, checks to see whether the address of the write corresponds to a particular watchpoint, and then either resumes or drops to the gdb command prompt accordingly. You can

问题 In Objective-C, I would sometimes set watchpoints in LLDB to let me know when instance variables had changed. Can I do this with Swift properties too? Right now, the only way I can achieve this is: adding a didSet handler to the property and setting a breakpoint inside (but this requires stopping the program and recompiling, which kind of defeats the purpose) adding a symbolic breakpoint on [setPropertyName:] but this only works if the class happens to support Objective-C bridging Do I have

问题 Say I define a variable named var in the main function. And the I set a watchpoint to it. Then I enter another function called func() . At this time, the watchpoints may be deleted so that I have no access to that variable. Any method to make to possible to always keep the watchpoint whenever you are? Also, I know I can use syntax like print main::var to print out the value of the variable. But that is not sufficient enough. Any good idea? 回答1: An oddity of gdb is that watch tries to respect

问题 If I try to set a watchpoint I get a gdb error: " can't clear hardware watchpoints without the 'Z2' (write-watchpoint) packet " Then it seems to corrupt the device (on restarting the device it complains that the OS is too old for the SDK, even though it's OS 3.1.2). I've got a bug to track down that really would be easy to track down with a watchpoint so this really is a pain. Anybody know if watchpoints are supposed to work? How to get them to work? 回答1: Unfortunately this is a known bug in

问题 I am trying to track a change of a value using watchpoint in a Java program in Eclipse debugger. The class hierarchy is pretty complex and the value I am tracking is wrapped in container, which is used on many places. To be more specific, there is a container SizeRequirement , which has a property minimum , which I am tracking. This class is used by many layout managers on many places for many components to define requirement for component's sizes. I need to catch exact call, where the value