C / C++ / MFC

Re: Application launched by another program, how to debug?

6-Mar-18 15:49

ooookay, I didn't expect that answer. Totally new to me, I'll look into it.

Randor 6-Mar-18 17:20

Randor

6-Mar-18 17:20

charlieg wrote:
ooookay, I didn't expect that answer.

Liquid Nitrogen. It's what I use for branding my cattle[^].

charlieg wrote:
Totally new to me

I highly recommend learning how to use all of the debugging tools.

Best Wishes,
-David Delaune

Re: Application launched by another program, how to debug?

charlieg7-Mar-18 4:13

Re: Application launched by another program, how to debug?

7-Mar-18 4:13

Lol, just perused the gflags area. Might be a little heavy for what I need, but very interesting items.

Thanks

Randor 7-Mar-18 5:36

Randor

7-Mar-18 5:36

charlieg wrote:
Might be a little heavy for what I need, but very interesting items.

Two thoughts:

1.) If you actually want to debug an error occuring when ProgramB is launched from ProgramA. There is no other way.

2.) If your question was worded incorrectly and you just simply need to debug ProgramB then just attach a debugger to it.

Best Wishes,
-David Delaune

Re: Application launched by another program, how to debug?

Richard MacCutchan6-Mar-18 22:39

Re: Application launched by another program, how to debug?

6-Mar-18 22:39

Assuming that test.exe is a Debug version, or you have the source, you can just launch it directly from Visual Studio. But if it is not a Debug version you will not get much useful information from the debugger.

[edit]
Also you can attach the debugger to a running process.
[/edit]

charlieg7-Mar-18 4:15

Re: Application launched by another program, how to debug?

7-Mar-18 4:15

I have the debug code, so this approach might work. I normally live in the embedded world, and the magic of attaching to running processes to debug is mostly a foreign concept.

I hope this works....

Richard MacCutchan7-Mar-18 4:35

Implication of assign a value at function entry

7-Mar-18 4:35

It helps to have all the source code also, and/or the .PDB file with the debug information, so you can see proper details of what is going on. Sounds complicated, but it's really useful.

ForNow6-Mar-18 8:13

Re: Implication of assign a value at function entry

6-Mar-18 8:13

Hi
I am getting a local variable overlayed now I am beginning to think it maybe because of the way I declared it

for example void process_trace()
{
char BASSM[2] = {0X0C, 0XEF};

This is still considered a local variable even though its assigned value since I didn't use the key word static

So I guess on entry to the function the complier re-initializes the value everytime
I guess I am thinking since this variable is some how being overlayed and I am not changing the value I should make it static

Thanks

Richard MacCutchan6-Mar-18 9:09

Re: Implication of assign a value at function entry

6-Mar-18 9:09

Where is it getting overlayed?

ForNow6-Mar-18 9:25

Re: Implication of assign a value at function entry

6-Mar-18 9:25

I made a DATA breakpoint in Visual Studio and the overlay was some where deep in Windows in ntdll I did a Call Stack and it wasn't in the function that BASSM was declared
truth is at the very least since the value of BASSM is not being changed I should qualify it with a const to save compiler the trouble of initializing it every time

Richard MacCutchan6-Mar-18 9:29

Re: Implication of assign a value at function entry

6-Mar-18 9:29

No, you should first find out where it is being overwritten and why. This error tells you that you have a bug in your code, so rather than try to hide it, you need to fix it. But without seeing more of your code it is difficult to guess what might be the cause.

ForNow6-Mar-18 9:34

Re: Implication of assign a value at function entry

6-Mar-18 9:34

I could post all the code in the function but I don't think that would help

I'll spend tonite trying to figure it and regardless I'll re-declare BASSM as const

that still shouldn't stop the bug as its still a local stack variable

thanks

Richard MacCutchan6-Mar-18 9:37

Re: Implication of assign a value at function entry

6-Mar-18 9:37

ForNow wrote:
I'll re-declare BASSM as const

Well, good luck, but you still have a bug in your code.

ForNow6-Mar-18 9:39

Re: Implication of assign a value at function entry

6-Mar-18 9:39

I’ll post it tommorow if I don’t get anywhere it is not clearly apperent as I never move anything into BASSM

Thanks

jeron16-Mar-18 9:50

jeron1

6-Mar-18 9:50

For clarification the value of BASSM is different at the end of the process_trace() method, than the initialized value?

"the debugger doesn't tell me anything because this code compiles just fine" - random QA comment
"Facebook is where you tell lies to your friends. Twitter is where you tell the truth to strangers." - chriselst
"I don't drink any more... then again, I don't drink any less." - Mike Mullikins uncle

Re: Implication of assign a value at function entry

ForNow6-Mar-18 10:10

Re: Implication of assign a value at function entry

6-Mar-18 10:10

the first byte of the BASSM X'0C' gets overlayed not sure where I am going to have to step thru process_trace and check BASSM intermittently

Thanks

jeron16-Mar-18 10:35

jeron1

6-Mar-18 10:35

If it get overwritten consistently, stepping through the method is the way to go.

Re: Implication of assign a value at function entry

Richard MacCutchan6-Mar-18 10:47

Re: Implication of assign a value at function entry

6-Mar-18 10:47

Set a watchpoint on it in the debugger: Watch and QuickWatch Windows[^]

ForNow6-Mar-18 11:07

Re: Implication of assign a value at function entry

6-Mar-18 11:07

Thanks

ForNow7-Mar-18 4:57

Re: Implication of assign a value at function entry

7-Mar-18 4:57

There was a VFETCH macro which basically copied over data from the Mainframe emulated storage to your program the macro had a length however it would append a NULL (CString Style) at the end so even though I specified 4 bytes it put a null at the 5 th byte

The local storage the way it is laid out by the compiler is not the way it’s declared in the function so even though the area the VFETCH macro was using wasn’t declared after the BASSM the compiler laid it out that way and the VFETCH overlaid the 1st byte of BASSM
I fixed this problem but I also moved the BASSM to global storage by making it static

Thanks for all the help

Richard MacCutchan7-Mar-18 5:02

Re: Implication of assign a value at function entry

7-Mar-18 5:02

charlieg6-Mar-18 13:38