www.digitalmars.com         C & C++   DMDScript  

digitalmars.D - How to find where "Access Violation" occurs ?

reply "Shawn Liu" <liuxuhong.cn gmail.com> writes:
We always encounter "Access Violation" error when work with D. Especially,
when port C++/Java to D. The application just crash and says "Access
Violation" error in the console, but doesen't tell you where the error
occurs.

For a small file, a "Access Violation" can be checked line by line.
Where != or !== mismatched, where we access members of a null Object and
etc.
But for a large project with hundreds files, you can't do it easily.

You may say place breakpoints and debug it step by step. But for a GUI app,
you don't known where to place the breakpoints. Debug with keyboard and
mouse messege proccessing will prevent you enter some situation. It is like
that when debug with bp, app never crash. when run freely, app collapsed.

My questions :

1) What causes a "Access Violation", null Object, !=/!== and ...??
2) Can dmd printf where a "Access Violation" occurs. __FILE__, __LINE__ is
okay

BTW,
1) DMD doesn't check whether all path of a function return a value just like
C++/Java compiler does at compile time. Assert error at runtime when a
return absent for a function.
2) App crash when a default absent in a switch block. DMD can't detect it at
compile time. Runtime error with message "switch default".

Shawn
Apr 19 2005
next sibling parent reply Thomas Kuehne <thomas-dloop kuehne.thisisspam.cn> writes:
Shawn Liu schrieb am Tue, 19 Apr 2005 19:01:10 +0800:

 BTW,
 1) DMD doesn't check whether all path of a function return a value just like
 C++/Java compiler does at compile time. Assert error at runtime when a
 return absent for a function.
 2) App crash when a default absent in a switch block. DMD can't detect it at
 compile time. Runtime error with message "switch default".


use "dmd -w source.d"
Apr 19 2005
parent "Shawn Liu" <liuxuhong.cn gmail.com> writes:
Thanks. This is help.

"Thomas Kuehne" <thomas-dloop kuehne.thisisspam.cn>
写入消息新闻:s65fj2-nj3.ln1 lnews.kuehne.cn...

 Shawn Liu schrieb am Tue, 19 Apr 2005 19:01:10 +0800:

 BTW,
 1) DMD doesn't check whether all path of a function return a value just 
 like
 C++/Java compiler does at compile time. Assert error at runtime when a
 return absent for a function.
 2) App crash when a default absent in a switch block. DMD can't detect it 
 at
 compile time. Runtime error with message "switch default".


 use "dmd -w source.d"
Apr 19 2005
prev sibling parent reply aleko <aleko_member pathlink.com> writes:
I use WinDbg for tracking down memory-related crashes. Open the executable, and
run it. When it crashes, run the '!analyze -v' command to get a (very) detailed
analysis. BTW, compile with -g to add symbolic debugging info.
Apr 19 2005
parent reply Sean Kelly <sean f4.ca> writes:
In article <d435rj$s3l$1 digitaldaemon.com>, aleko says...

I use WinDbg for tracking down memory-related crashes. Open the executable, and
run it. When it crashes, run the '!analyze -v' command to get a (very) detailed
analysis. BTW, compile with -g to add symbolic debugging info.


Have you gotten WinDbg to display the contents of variables, or do you just
inspect memory directly?


Sean
Apr 19 2005
parent reply aleko <aleko_member pathlink.com> writes:
Have you gotten WinDbg to display the contents of variables, or do you just
inspect memory directly?


Unfortunately, no. The DMD compiler doesn't generate the .PDB files that WinDbg
needs to in order to do that. I have heard that Visual Studio can debug D
executables, and inspect symbols, but I haven't done this myself. Maybe someone
else can comment on this?

-Aleko
Apr 19 2005
next sibling parent "Regan Heath" <regan netwin.co.nz> writes:
On Wed, 20 Apr 2005 03:39:26 +0000 (UTC), aleko  
<aleko_member pathlink.com> wrote:

 Have you gotten WinDbg to display the contents of variables, or do you  
 just inspect memory directly?


 Unfortunately, no. The DMD compiler doesn't generate the .PDB files that  
 WinDbg
 needs to in order to do that. I have heard that Visual Studio can debug D
 executables, and inspect symbols, but I haven't done this myself. Maybe  
 someone
 else can comment on this?


http://www.prowiki.org/wiki4d/wiki.cgi?DebugEnvironments#MSDEVMSVisualStudio

Same problem, it does not "know" about D's arrays. So the best you can do  
is inspect the memory directly. Thanks to Arcane Jill for this quote...

<AJ>
First, you have to get your numbers displayed in hex, not in decimal. In  
this case 35518073867862116 happens to be 0x7E2F800000000064. So the high  
half - 0x7E2F8000 - is the address of the array in memory, and the low  
half - 0x00000064 - is the number of elements in the array.
</AJ>

Regan
Apr 19 2005
prev sibling parent "Shawn Liu" <liuxuhong.cn gmail.com> writes:
Yes, you can build and debug D source files in Visual Studio.

And here I have written a tool to simplify the build job.

http://www.dnaic.com/d/en/bldtool.htm


Shawn Liu


"aleko" <aleko_member pathlink.com> says : 
d44ite$26mr$1 digitaldaemon.com...

Have you gotten WinDbg to display the contents of variables, or do you 
just
inspect memory directly?


 Unfortunately, no. The DMD compiler doesn't generate the .PDB files that 
 WinDbg
 needs to in order to do that. I have heard that Visual Studio can debug D
 executables, and inspect symbols, but I haven't done this myself. Maybe 
 someone
 else can comment on this?

 -Aleko
Apr 20 2005