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dotnet compact framework
group:HELP !! pb calling eVC++ DLL from VB.NET on compact framework
dotnet compact framework:
i need your HELP ! (it's long to explain but it's needed) i have a big problem (for me) with my APP/DLL i have made an Application with VB.NET for Compact framework that call an DLL written in eVC++ 4. the pb is i get a "First-chance exception ... Access violation" sometimes... before my VB app are small (and i haven't the pb) but now is bigger (and i have the pb all the time). when i debug the DLL, at the exception if i continu, i often get a "stack overflow".. i have read many things on the net but i haven't found a solution for the pb. it seem its a limit of 4k(or 64k) boundary page pb with the stack.. here the start of my DLL function : char __declspec(dllexport) f_com_ReadAcq(char voie,double * pValeurs, int *nbValeur) { UCHAR buffer[120000]; long sizeBuf=0; ReceiveData_GetLast(&tdReceiveMemory, buffer,500, RECEIVE_DATA_ACQ, voie ,&sizeBuf); ... ... } in ReceiveData_GetLast i do some memcpy to "buffer" and it's these memcpy that do exception...i have try to replace the memcpy by a soft loop then it crash at same time.. the DLL function is called from many place on the vb.net app then in one case (always the same) it work... when it work, the &buffer = 0x2207F2CC when it crash the &buffer = 0x22011f8c when it crash the pointer to buffer = 0x22012000 i mean it's the 1FFF to 2000 boudary that cause crash...(4k page ??) i mean i can use malloc to allocate my 120k buffer, but i'm afraid for the rest of development...if i have only 116 bytes of local memory available (0x22012000 - 0x22011f8c)...then this problem can appairs later in development even if i make all array with malloc............ can it be VB.NET that fill the stack ?and how i can do to "free" some bytes of the stack before calling DLL...? thank a lot for all people that can help me....(i'm on this pb since 3 days now and my app is not finished.....) Eric BOUXIROT (sorry for my bad english) you can answer me at bouxirot@lgm.fr
Ilya,
This thread is an orphan. The continuing thread is in the eVC newsgroup. In fact, though, the allocation of the local, *not* its use, is responsible for the exception. See my code to duplicate the problem in the other newsgroup (same thread name). Paul T. [quoted text, click to view] ""Ilya Tumanov [MS]"" <ilyatum@online.microsoft.com> wrote in message news:bTOS9Dx1EHA.768@cpmsftngxa10.phx.gbl... >I don't think it's related to VB and pages. That seems to be a very common > bug in your native code called "buffer overflow". > > Here's an example: > > UCHAR buffer[10]; > ... > bufferr[100] = 0; // Oops. > memcpy (buffer, NULL, 100); // Oops and... oops. > > Most likely memcpy() in ReceiveData_GetLast() copies more than 120000 > bytes > for some reason or uses invalid pointer(s). > Add some verification code to ReceiveData_GetLast() to verify array > boundaries/pointers and pop up an assert in case of a problem. > That would help you figure out what's wrong. Also, it's a good idea to add > some check and return an error if data appears to be incorrect. > > You should pass buffer size to ReceiveData_GetLast() so it won't copy too > much: > > UCHAR buffer[120000]; > .. > long sizeBuf=sizeof(buffer); > .. > > In ReceiveData_GetLast(): > > size = ... ; // Where it's coming from? Can it be wrong? > source = ... ; // Where it's coming from? Can it be wrong? > > ASSERT (buffer != NULL); > ASSERT (source != NULL); > ASSERT (sizeBuf > size); > > // consider adding check and return an error instead of crashing. > .. > memcpy (buffer, source, size); > > Best regards, > > Ilya > > This posting is provided "AS IS" with no warranties, and confers no > rights. > > -------------------- >> Reply-To: "Rick" <rickou@rickou.net> >> From: "Rick" <rickou@rickou.net> >> Newsgroups: > microsoft.public.windowsce.embedded.vc,microsoft.public.dotnet.framework.com > pactframework,microsoft.public.dotnet.languages.vb,microsoft.public.windowsc > e.embedded.vb >> Followup-To: microsoft.public.windowsce.embedded.vc >> Subject: HELP !! pb calling eVC++ DLL from VB.NET on compact framework >> Date: Tue, 30 Nov 2004 11:18:06 +0100 >> X-Priority: 3 >> X-MSMail-Priority: Normal >> X-Newsreader: Microsoft Outlook Express 6.00.2900.2180 >> X-RFC2646: Format=Flowed; Original >> X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 >> Lines: 65 >> Message-ID: <41ac48e2$0$2209$626a14ce@news.free.fr> >> Organization: Guest of ProXad - France >> NNTP-Posting-Date: 30 Nov 2004 11:18:10 MET >> NNTP-Posting-Host: 82.225.255.72 >> X-Trace: 1101809890 news10-e.free.fr 2209 82.225.255.72:1305 >> X-Complaints-To: abuse@proxad.net >> Path: > cpmsftngxa10.phx.gbl!TK2MSFTNGXA03.phx.gbl!TK2MSFTNGP08.phx.gbl!newsfeed00.s > ul.t-online.de!t-online.de!news.zanker.org!npeer.de.kpn-eurorings.net!proxad > net!infeed-1.proxad.net!news10-e.free.fr!not-for-mail >> Xref: cpmsftngxa10.phx.gbl > microsoft.public.dotnet.framework.compactframework:66026 > microsoft.public.dotnet.languages.vb:245829 > microsoft.public.windowsce.embedded.vb:21461 > microsoft.public.windowsce.embedded.vc:36880 >> X-Tomcat-NG: microsoft.public.dotnet.framework.compactframework >> >> hi all ! >> >> i need your HELP ! (it's long to explain but it's needed) >> >> i have a big problem (for me) with my APP/DLL >> >> i have made an Application with VB.NET for Compact framework that call an >> DLL written in eVC++ 4. >> >> the pb is i get a "First-chance exception ... Access violation" > sometimes... >> >> before my VB app are small (and i haven't the pb) but now is bigger (and >> i >> have the pb all the time). >> >> when i debug the DLL, at the exception if i continu, i often get a "stack >> overflow".. >> >> i have read many things on the net but i haven't found a solution for the >> pb. it seem its a limit of 4k(or 64k) boundary page pb with the stack.. >> here the start of my DLL function : >> >> char __declspec(dllexport) f_com_ReadAcq(char voie,double * pValeurs, int >> *nbValeur) >> { >> UCHAR buffer[120000]; >> long sizeBuf=0; >> >> ReceiveData_GetLast(&tdReceiveMemory, buffer,500, RECEIVE_DATA_ACQ, voie >> ,&sizeBuf); >> .. >> .. >> } >> >> in ReceiveData_GetLast i do some memcpy to "buffer" and it's these memcpy >> that do exception...i have try to replace the memcpy by a soft loop then > it >> crash at same time.. >> >> the DLL function is called from many place on the vb.net app then in one >> case (always the same) it work... >> >> when it work, the &buffer = 0x2207F2CC >> when it crash the &buffer = 0x22011f8c >> when it crash the pointer to buffer = 0x22012000 >> >> i mean it's the 1FFF to 2000 boudary that cause crash...(4k page ??) >> >> i mean i can use malloc to allocate my 120k buffer, but i'm afraid for >> the >> rest of development...if i have only 116 bytes of local memory available >> (0x22012000 - 0x22011f8c)...then this problem can appairs later in >> development even if i make all array with malloc............ >> >> can it be VB.NET that fill the stack ?and how i can do to "free" some > bytes >> of the stack before calling DLL...? >> >> thank a lot for all people that can help me....(i'm on this pb since 3 > days >> now and my app is not finished.....) >> >> Eric BOUXIROT >> (sorry for my bad english) >> >> you can answer me at bouxirot@lgm.fr >> >> >> >> >> >
I don't think it's related to VB and pages. That seems to be a very common
bug in your native code called "buffer overflow". Here's an example: UCHAR buffer[10]; ... bufferr[100] = 0; // Oops. memcpy (buffer, NULL, 100); // Oops and... oops. Most likely memcpy() in ReceiveData_GetLast() copies more than 120000 bytes for some reason or uses invalid pointer(s). Add some verification code to ReceiveData_GetLast() to verify array boundaries/pointers and pop up an assert in case of a problem. That would help you figure out what's wrong. Also, it's a good idea to add some check and return an error if data appears to be incorrect. You should pass buffer size to ReceiveData_GetLast() so it won't copy too much: UCHAR buffer[120000]; ... long sizeBuf=sizeof(buffer); ... In ReceiveData_GetLast(): size = ... ; // Where it's coming from? Can it be wrong? source = ... ; // Where it's coming from? Can it be wrong? ASSERT (buffer != NULL); ASSERT (source != NULL); ASSERT (sizeBuf > size); // consider adding check and return an error instead of crashing… …. memcpy (buffer, source, size); Best regards, Ilya This posting is provided "AS IS" with no warranties, and confers no rights. -------------------- [quoted text, click to view] > Reply-To: "Rick" <rickou@rickou.net> microsoft.public.windowsce.embedded.vc,microsoft.public.dotnet.framework.com> From: "Rick" <rickou@rickou.net> > Newsgroups: pactframework,microsoft.public.dotnet.languages.vb,microsoft.public.windowsc e.embedded.vb [quoted text, click to view] > Followup-To: microsoft.public.windowsce.embedded.vc cpmsftngxa10.phx.gbl!TK2MSFTNGXA03.phx.gbl!TK2MSFTNGP08.phx.gbl!newsfeed00.s> Subject: HELP !! pb calling eVC++ DLL from VB.NET on compact framework > Date: Tue, 30 Nov 2004 11:18:06 +0100 > X-Priority: 3 > X-MSMail-Priority: Normal > X-Newsreader: Microsoft Outlook Express 6.00.2900.2180 > X-RFC2646: Format=Flowed; Original > X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 > Lines: 65 > Message-ID: <41ac48e2$0$2209$626a14ce@news.free.fr> > Organization: Guest of ProXad - France > NNTP-Posting-Date: 30 Nov 2004 11:18:10 MET > NNTP-Posting-Host: 82.225.255.72 > X-Trace: 1101809890 news10-e.free.fr 2209 82.225.255.72:1305 > X-Complaints-To: abuse@proxad.net > Path: ul.t-online.de!t-online.de!news.zanker.org!npeer.de.kpn-eurorings.net!proxad .net!infeed-1.proxad.net!news10-e.free.fr!not-for-mail [quoted text, click to view] > Xref: cpmsftngxa10.phx.gbl microsoft.public.dotnet.framework.compactframework:66026 microsoft.public.dotnet.languages.vb:245829 microsoft.public.windowsce.embedded.vb:21461 microsoft.public.windowsce.embedded.vc:36880 [quoted text, click to view] > X-Tomcat-NG: microsoft.public.dotnet.framework.compactframework
> > hi all ! > > i need your HELP ! (it's long to explain but it's needed) > > i have a big problem (for me) with my APP/DLL > > i have made an Application with VB.NET for Compact framework that call an > DLL written in eVC++ 4. > > the pb is i get a "First-chance exception ... Access violation" sometimes... > > before my VB app are small (and i haven't the pb) but now is bigger (and i > have the pb all the time). > > when i debug the DLL, at the exception if i continu, i often get a "stack > overflow".. > > i have read many things on the net but i haven't found a solution for the > pb. it seem its a limit of 4k(or 64k) boundary page pb with the stack.. > here the start of my DLL function : > > char __declspec(dllexport) f_com_ReadAcq(char voie,double * pValeurs, int > *nbValeur) > { > UCHAR buffer[120000]; > long sizeBuf=0; > > ReceiveData_GetLast(&tdReceiveMemory, buffer,500, RECEIVE_DATA_ACQ, voie > ,&sizeBuf); > .. > .. > } > > in ReceiveData_GetLast i do some memcpy to "buffer" and it's these memcpy > that do exception...i have try to replace the memcpy by a soft loop then it > crash at same time.. > > the DLL function is called from many place on the vb.net app then in one > case (always the same) it work... > > when it work, the &buffer = 0x2207F2CC > when it crash the &buffer = 0x22011f8c > when it crash the pointer to buffer = 0x22012000 > > i mean it's the 1FFF to 2000 boudary that cause crash...(4k page ??) > > i mean i can use malloc to allocate my 120k buffer, but i'm afraid for the > rest of development...if i have only 116 bytes of local memory available > (0x22012000 - 0x22011f8c)...then this problem can appairs later in > development even if i make all array with malloc............ > > can it be VB.NET that fill the stack ?and how i can do to "free" some bytes > of the stack before calling DLL...? > > thank a lot for all people that can help me....(i'm on this pb since 3 days > now and my app is not finished.....) > > Eric BOUXIROT > (sorry for my bad english) > > you can answer me at bouxirot@lgm.fr > > > > >
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