Re: [libsmi] memory leak; program terminates

11 Jan 2002


      Hi Arie.
I have performed two project with libsmi during six months.
The libsmi was not fault-tolerable.
At loadModule() and smiExit(), access violation error occured occasionally,
so exception handling must be done.
For loadModule() error occured by bad mib file and
for smiExit() i don't know.
I recommend following exception handling.
SmiModule* smiModule;
try
{
 char* name = smiLoadModule(moduleName.c_str());
 smiModule = name ? smiGetModule(name) : NULL;
}
catch(...)
{
...
 try{
  smiExit();
 }
 catch(...)
 {
  ...
 }
...
}
Termination is serious more than memory leak?
----- Original Message ----- 
From: "Arie Trost" ariet@genesyslab.com
To: "'Frank Strauss'" strauss@ibr.cs.tu-bs.de
Cc: libsmi@ibr.cs.tu-bs.de
Sent: Friday, January 11, 2002 8:30 AM
Subject: RE: [libsmi] memory leak; program terminates
...
Hi Frank,
I've tracked down the crash to the point where the loadModule() function
calls to yyparse.
When running my test program outside Microsoft Visual C++, I don't see any
warning or error messages at all, the program just terminates 
But when running in Visual C++ debugger, I am getting messages like these (a
snippet)
at the time of a crash:
Detected memory leaks!
   Dumping objects ->
  {6846} normal block at 0x026C1948, 1258 bytes long.
   Data: <The CounterBased> 54 68 65 20 43 6F 75 6E 74 65 72 42 61 73 65 64 
  {6844} normal block at 0x01C2FFE0, 20 bytes long.
   Data: <CounterBasedGaug> 43 6F 75 6E 74 65 72 42 61 73 65 64 47 61 75 67 
  {6843} normal block at 0x01C2E050, 44 bytes long.
   Data: <N               > 4E 00 00 00 08 00 00 00 00 00 00 00 00 00 00 00 
   ...
   ...
Actually, as you will see, there is memory leak after each call to
smiLoadModule()! 
There are several articles at MSDN describing how to detect memory leaks
in Visual C++ runtime system.
One way to do this is to dump memory leak information at the points of
interest
in the code using the _CrtDumpMemoryLeaks() function.
So, calling _CrtDumpMemoryLeaks() after smiLoadModule() will produce 
memory leak warning (similar to that above).
The same happens in smidump (which I've built in a separate Visual C++
project).   
However, it's only my DLL that would crash, not smidump :(
Any hints how one could better trace the parsing process (debug the Bison
parser and the relevant components within the libsmi itself). Any other
suggestions?
Thank you.
Arie.
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Re: [libsmi] memory leak; program terminates

Kang, Jeongwon