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HI all!
I m calling a function by a pointer of an external class & that pointer has been defined in the parent class of the class from which the already specified function is being called. The pointer's class is linked with the parent class (through its header).
So, the scenario is that a function accesses the protected member of a parent class (pointer) & then uses that member to call a function.
Now, when i compile the code, LNK2001/LNK1120 error is thrown.
Can any body tell me y this problem occured & what about its remedy?
Regards
Usman Arif
Usman Arif
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External as in not part of your project ? Have you linked to the appropriate .lib files ?
Christian Graus - Microsoft MVP - C++
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External means another application.
infact, i m integrating the dll of my project in an application (external). Now, in the next step, i m trying to access a class from the external application. For this, i included the header in my project. It worked fine uptil now. But, when i try to access a function from that external class, the linking error was thrown.
Usman Arif
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OK, so you need to take the .lib file from when you build that external dll, and link to it.
Christian Graus - Microsoft MVP - C++
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Hello Mr arif,
you misunderstood MR Graus. He is saying that you forget to include .lib file which contain the runtime symbol for you external class(i.e. class from DLL).
"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow
cheers,
Alok Gupta
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The external application, i m using, has an .exe file as its output file.
I converted the output file to .lib file & then included it into my project, but the error is LNK1136 ,i.e. "Invalid or corrupt file".
Usman Arif
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Usman Arif wrote:
The external application, i m using, has an .exe file as its output file.
Buddy I am here talking about .LIB file which will produce with the DLL (when you build it). you can find that .lib in DEBUG/RELEASE folder of DLL project
"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow
cheers,
Alok Gupta
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Friend!
That .lib file is already there, no problem with that.
My problem is that i wanna access the external application's (in which .lib of my project was included already)function from my project.
now, r u clear with my problem? if yes, suggest some remedy for it; if possible.
Usman Arif
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i can't seem to find matlab.h in my matlab7 folders or my visual stuido6.0 folders. Where can i get it
Thanks in advance
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Do you have the rest of matlab, but not the .h file ? If not, then the .h file is of no use to you.
It sounds like you have it installed ( you have a matlab7 folder ), so do a system wide search for it. If you can't find it, I'd suggest that finding a copy of that file is a waste of time. If you're missing one file for some reason, you may be missing others, and a reinstall of matlab is the only sensible option IMO.
Christian Graus - Microsoft MVP - C++
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i think i have the rest. Do u think i can download it somewhere? Because i don't think reinstalling will help.
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um.... dude, if reinstalling it won't help, then your setup is fundamentally broken. If that file is not in your setup, and you need it, then your setup file is broken, or you're looking for the wrong thing.
No, I've never used matlab. It's a library for image processing, right ? I have written a lot of image processing code in C++ and C#, but the only external library I ever used was paintlib, and GDI+ makes that redundant.
Christian Graus - Microsoft MVP - C++
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Did you install the MATLAB Compiler Toolbox? What about MATLAB C/C++ MATH Library?
Best regards,
A. Riazi
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What are you trying to do. I have MATLAB and a lot of toolboxes. MATLAB.h is not in my installation either. I have never run across anything that needs that include file.
If you are simply trying to call the matlab engine from your own program, you need engine.h. Also, look at the CP articles by A. Riazi and there is an online tutorial on Matlab's website.
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Thanks for the response guys. I think I know what is wrong with the program. My friend emailed me this:
http://www.mathworks.com/support/solutions/data/1-TUUKR.html?solution=1-TUUKR
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which one is better to use either union or struct.
rajesh
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Depends what you want to do. The point of a union is that you have one value only, and you can change it's type ( that is, you can store an int or a string (for example), not that it has inbuilt conversion between types ). The point of a struct is to collect a group of values. Here's a link to what a union is.
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vccelng/htm/class_29.asp[^]
A struct is a class whose default access is public. They both exist because they do two different things.
Christian Graus - Microsoft MVP - C++
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Rajesh_K_Sharma wrote:
which one is better to use either union or struct.
Depends on Situations.But, personally I have never liked Union!.
"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow
cheers,
Alok Gupta
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ThatsAlok wrote:
personally I have never liked Union!.
sometimes, it become THE feature to be used... 
i remember a project i made last year, when i was programming for a microprocessor... we had to know how the processor memory was, where would be stored the hardware datas, and to implement this (wheter the periph was reading or writing), the datas was in distinct registries. but sometimes happend the fact that those two registries were at the same address...
so, what to use ? unions... 
but i agree, it's not the most easy thing to learn about from C.
TOXCCT >>> GEII power
[toxcct][VisualCalc]
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toxcct wrote:
when i was programming for a microprocessor... we had to know how the processor memory was,
Hi Tox,
As I don't program in MicroController/hardware, Unions would never be my first Choice.
That's just my personel feeling, I am not forcing any BODY to use structure instead of UNIONS.
It's always DEPENDS ON SITUATION which one is better,
let takes a example,if you want to keep Name and age of employee in a DATA STRUCTURE, your choice always would be STRUCTURE (in case of C ) as you don't want to mess up the data!.
"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow
cheers,
Alok Gupta
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ThatsAlok wrote:
It's always DEPENDS ON SITUATION which one is better
that's logic, i entierly agree with you sir...
TOXCCT >>> GEII power
[toxcct][VisualCalc]
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toxcct wrote:
sir...
 .............It's a great Pleasure!
"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow
cheers,
Alok Gupta
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This means that you have never needed union. There is nothing to like or not to like. In fact, the union was introduced by John von Neumann (first computer idea creator) at the beginning of 20th century, if I'm not wrong, when he presented interpretting of a memory word once as a machine code or secondly as a piece of data. Thus you have the ancient union .
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liquid_ wrote:
This means that you have never needed union
Hello Mr Liquid,
I Believe, I am repeating myself i am application developer, It's really depend upon situation of project which thing will be better. you don't want to mess data of Student Name, Age and Class by using the UNION.
yeah i know UNION ar emuch better in other cases as mentioned by Mr Tox!
Thanks
"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow
cheers,
Alok Gupta
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using union is good think if u really know where to use n how to use it.
I pesonaly use union as annonymous inside class or struct coz suppose if u have more than one embeded class-object in some class n want to select any one of it then u can use union to allocate memory only for one of that, so no need to allocate memory for each n every embeded class-object, so union is good to use
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