|
For debugging purposes, I am going to be basically hijacking a function that handles a variable argument list. This function convers the Variable Argument List (VAL) into a va_list variable and passes it to another function to process the variable argument list (like how one would make a call to _vsntprintf).
I can descern the number and types of arguments from other parameters passed to the function, so I want to be able to trace information on the parameters passed. My question is this - it is safe (not possible, but safe) to call va_start multiple times on the same va_list variable (in the same function) to reset the VAL?
I cannot find code that does this, nor information that details the safety of doing so.
Thoughts?
Thanks!
Peace!
-=- James
If you think it costs a lot to do it right, just wait until you find out how much it costs to do it wrong!
Avoid driving a vehicle taller than you and remember that Professional Driver on Closed Course does not mean your Dumb Ass on a Public Road!
DeleteFXPFiles & CheckFavorites (Please rate this post!)
|
|
|
|
|
I've never encountered a mention of this scenario myself, but from the possibilities to implement this, it is OK. (the two implementation I've seen so far use a pointer to thestack, initialized by va_start, incremented by va_arg, and a do-nothing operation in va_end)
The question is: how portable do you need it?
Some of us walk the memory lane, others plummet into a rabbit hole
Tree<t> in C# || Fold With Us! || sighist
|
|
|
|
|
There are no portability concerns here - this is, and always will be, a Win32 implementation. Only concerns would be compiler differences if/when this implementation is built on a newer version of the compiler.
My concern is one of works vs. correct. It might work, but is it correct to do so, so I will not expect any side-effects in the future.
I do not expect it to be a problem, because va_start just resets the internal pointer to the beginning of the argument list, and there seems to be no other state stored outside of calls to va_arg, but it is always worth asking to make sure noone else has tried this and bombed! 
Thanks!
Peace!
-=- James
If you think it costs a lot to do it right, just wait until you find out how much it costs to do it wrong!
Avoid driving a vehicle taller than you and remember that Professional Driver on Closed Course does not mean your Dumb Ass on a Public Road!
DeleteFXPFiles & CheckFavorites (Please rate this post!)
|
|
|
|
|
James R. Twine wrote: but it is always worth asking to make sure noone else has tried this and bombed!
tell us if it does 
Some of us walk the memory lane, others plummet into a rabbit hole
Tree<t> in C# || Fold With Us! || sighist
|
|
|
|
|
Not only safe, it's part of the design. To be technically correct, you should use va_end before using va_start the second time, though in VC++, it doesn't really matter (since it allocs no memory.)
Anyone who thinks he has a better idea of what's good for people than people do is a swine.
- P.J. O'Rourke
|
|
|
|
|
James R. Twine wrote: My question is this - it is safe (not possible, but safe) to call va_start multiple times on the same va_list variable (in the same function) to reset the VAL?
Yes. No problems at all. I've done it a few times. For safety, call va_end() in between, but in Win32, it's not required in any implementation I've seen. Other OSes might need it though.
Ryan "Punctuality is only a virtue for those who aren't smart enough to think of good excuses for being late" John Nichol "Point Of Impact"
|
|
|
|
|
I am geeting error
"cannot convert parameter 2 from 'char *' to 'LPCWSTR' Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast"
I think we need to change character set from UNICODE to MULTIBYTE( _MBCS instead of _UNICODE ) It gets compiled on VC6. The reason may be at that time the default character set wasn't Unicode.
I don't want to use _T() macro.
We can change character set through IDE this way-
Go to project properties, select ConfigurationProperties, General and you have an option called Character Set. The default is Use Unicode Character Set. Change it to Use Multi-Byte character set.
But how this can be done through command prompt. I need to use /d
to change option of cl.exe. But how exactly it is done?
Vaibhav
|
|
|
|
|
I am trying to build a project on VC2005. We work on command promt
Vaibhav
|
|
|
|
|
Hello to all. I am searching for information about how I can create an additional plugin that can be installed on a browser. If anyone has an idea from where I might read something about how this is done I'll be very grateful for the help.
Regards, Tsvetelina Ivanova
|
|
|
|
|
Search for browser helper object (BHO).
"Let us be thankful for the fools. But for them the rest of us could not succeed." - Mark Twain
|
|
|
|
|
Am a novice in Vc++, actually, i wanted to call a function which outputs the data in Byte for repeted no of times to set the output data in an array(such a array of bytes), but am having compilation error? am using a "for loop" to call the function for no of times, until the output data is stored in an array. what am doing is right?is it possible to do so?
shrin
|
|
|
|
|
please show us your code to see what you're doing wrong, and tell exactly what the compiler returns you as an error !!
ps: put your code within <pre></pre> tags...
TOXCCT >>> GEII power
[toxcct][VisualCalc 2.24][3.0 soon...]
|
|
|
|
|
srija wrote: am using a "for loop"...
Have you seen here?
"Let us be thankful for the fools. But for them the rest of us could not succeed." - Mark Twain
|
|
|
|
|
hi,
i Create a application in ATL COM application,( for dll based application)
with simple get and set method for adding 2 nos
which is very similar to the link
http://www.codersource.net/atl_tutorial_events_properties.html[^]
but after build the appliaction i get error as
C:\Program Files\Microsoft Visual Studio\VC98\ATL\INCLUDE\atlcom.h(1827) : error C2259: 'CComObject<class csimpleobj="">' : cannot instantiate abstract class due to following members:
C:\Program Files\Microsoft Visual Studio\VC98\ATL\INCLUDE\atlcom.h(1823) : while compiling class-template member function 'long __stdcall ATL::CComCreator<class atl::ccomobject<class="" csimpleobj=""> >::CreateInstance(void *,const struct _GUID &,
void ** )'
C:\Program Files\Microsoft Visual Studio\VC98\ATL\INCLUDE\atlcom.h(1827) : warning C4259: 'long __stdcall ISimpleObj::total(void)' : pure virtual function was not defined
E:\templqw12\SimpleAtlCom\SimpleAtlCom.h(106) : see declaration of 'total'
C:\Program Files\Microsoft Visual Studio\VC98\ATL\INCLUDE\atlcom.h(1823) : while compiling class-template member function 'long __stdcall ATL::CComCreator<class atl::ccomobject<class="" csimpleobj=""> >::CreateInstance(void *,const struct _GUID &,
void ** )'
C:\Program Files\Microsoft Visual Studio\VC98\ATL\INCLUDE\atlcom.h(1827) : error C2259: 'CComObject<class csimpleobj="">' : cannot instantiate abstract class due to following members:
C:\Program Files\Microsoft Visual Studio\VC98\ATL\INCLUDE\atlcom.h(1823) : while compiling class-template member function 'long __stdcall ATL::CComCreator<class atl::ccomobject<class="" csimpleobj=""> >::CreateInstance(void *,const struct _GUID &,
void ** )'
C:\Program Files\Microsoft Visual Studio\VC98\ATL\INCLUDE\atlcom.h(1827) : warning C4259: 'long __stdcall ISimpleObj::total(void)' : pure virtual function was not defined
E:\templqw12\SimpleAtlCom\SimpleAtlCom.h(106) : see declaration of 'total'
C:\Program Files\Microsoft Visual Studio\VC98\ATL\INCLUDE\atlcom.h(1823) : while compiling class-template member function 'long __stdcall ATL::CComCreator<class atl::ccomobject<class="" csimpleobj=""> >::CreateInstance(void *,const struct _GUID &,
void ** )'
SimpleObj.cpp
reply me
send reply
|
|
|
|
|
Dear All
Can anyone help me to run a process before winlogon?
I have already tried to get the handle of winlogon with FindWindowEx but failed.
Please Help me.
Mohiul
My name is Mohiul,Nick name Rony
|
|
|
|
|
I think that you need to write a device driver in order to get something that you know will start before other system processes (you need a disk driver loaded in order to load winlogon from disk).
Peace!
-=- James
If you think it costs a lot to do it right, just wait until you find out how much it costs to do it wrong!
Avoid driving a vehicle taller than you and remember that Professional Driver on Closed Course does not mean your Dumb Ass on a Public Road!
DeleteFXPFiles & CheckFavorites (Please rate this post!)
|
|
|
|
|
A service might be what you are looking for. It depends on what problem you want to solve.
More information about services and how to write a service you will find here[^].
Hope this helps
--
Roger
It's supposed to be hard, otherwise anybody could do it!
|
|
|
|
|
Thanx for Replies.
I already running my application as a service.
But It activated after the windows logon.
My Aplication is a Scanner based application which will do something in
logon screen.
So please help me how I get the handle of winlogon???
Mohiul Rony
Programming is better than a lover...
-- modified at 23:05 Thursday 23rd February, 2006
|
|
|
|
|
mohiul wrote: Can anyone help me to run a process before winlogon?
You can create a service (they run without the need of anyone logging in).
You can also create an regular application and add it to the following registry key:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run
Items in this key run in the context of the machine and not any particular user.
"Let us be thankful for the fools. But for them the rest of us could not succeed." - Mark Twain
|
|
|
|
|
Hi,
I am running a unicode web application where data passed is in the form of MBCS. Now i am receiving 'Buffer Overrun Detected' error while connecting to CDatabase::OpenEX(). I have an application developed in VC++ (MFC).
BTW, connection string passed is in non-unicode format hence there should not be a problem in connecting to database.
One more point to notice is, I am getting this error in DEBUG mode and not in RELEASE mode.
Can anybody tell what is possibly the cause of the error?
Light thrown in this regard by anybody would be a great help to me.
Thanks for your time.
Nishith
|
|
|
|
|
meet2nishith wrote: Now i am receiving 'Buffer Overrun Detected' error while connecting to CDatabase::OpenEX().
What does this statement look like?
"Let us be thankful for the fools. But for them the rest of us could not succeed." - Mark Twain
|
|
|
|
|
Following string is passed as connection string which it successfully passes with CDatabase::Connect().
"ODBC;DSN=Corporate Directory;UID= corpdiruser;PWD= corpdiruser;APP=Internet Information Services;WSID=NISHITH;DATABASE=HRMSDB;Network=DBMSSOCN"
But when it comes back to same function, just after return TRUE; it fails and throws buffer overrun error. (_SECERR_BUFFER_OVERRUN)
|
|
|
|
|
Well Guys, ive got a query that why does crystal report control initialization is very slow. im facing this problem since ive installed crystal reports versions 10 n 11. it had better speed than 11 when i was using 9 version. if anyone knows the solution, please send me email at prog_irfan@yahoo.com
will b glad n thankful.
Irfan Shahid
Irfan Shahid
|
|
|
|
|
Hi,
I am new to vc++.
can anybody tell me what exactly applications we can write which are not able to write in any other language, i mean what is the exact purpose of vc++.I heard that it is useful for embedded applications. can anyone tell me other applications.
i will be thankful if u can suggest best sites which explain major advantages of vc++ otherthan any other language.
waiting 4 earliest reply
|
|
|
|
|
Apart from the application and web we can everything in vc++. applications developments area also possible in vc++ but constraint application development is not easy like vb or other applciation development tools.
Have A Nice Day!
Murali.M
|
|
|
|
General 
News 
Suggestion 
Question 
Bug 
Answer 
Joke 
Praise 
Rant 
Admin 
Submit an article or tip
