Place function in header file?

Hello, again.
Suppose I have a piece of code that I know I am going to be using very often. Obviously, the logical thing to do is place it in a function. And, suppose that I know I'm going to be calling that function often, and in a lot of different projects. How can I best make it so that I don't have to declare and define the function in every file in every project that I want to use this function in?
Would I place the function in a header file, and then use the #include preprocessor directive to include the .h file in every file I want to use the function in? If so, why couldn't I just store the function in a .c/.cpp file? What does a header file offer over a .c or .cpp file -- why use one over the other?
Also, where do I go to create the header file? If I go to File > New File and select header file, then it creates it as a file within the project that I have open at that moment, and I'm going to want to use the file in other projects. Is there somewhere I can save the header file outside of any specific project, so that I can include it in any project I want?
Thanks.

Tron55555 wrote:
So, technically, I could define the entire function in the header file, even without declaring it as inline, and I wouldn't have to define it in a source file?
Nope. You'll get linker errors, or at least warnings, about the function being defined twice.
1.) Why define it in a source file in the first place? Why not always define it in the header file? I can imagine there's obviously a very good reason for this -- I'm just curious what it is.
Code bloat and the sheer inefficiency of having the same code duplicated everywhere.
2.) You said that if the function is defined in the header file instead of a source file then it is treated as a macro and the whole function is picked up and dropped in your code wherever it is called. This sounds like the same thing as an inline function, so if you did define the entire function in the header file, what would be the difference between defining the whole thing in the header file using the inline keyword, versus defining the whole thing in the header file without the inline keyword?
Well, it is an inline function. You must use the inline keyword.
3.) Finally, if I did decide to define the entire function in the header file and not use a source file, would I still need to write the function signature as well, or just the definition?
Just the definition.

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I am trying to use Java methods into LV. I am doing so by creating Java Invocation Interface, usind which I can call Java methods into C++ and then create a shared library that can be called into LV.
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Attachments:
SharedLibError.png ‏51 KB

Hello Vivek,
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I presently have a site I created in Frontpage 2003, Gunshows-USA.com. It has seperate pages for each state and month. I had a header file called head.shmtl that I included on each page. This allowed me to create one file and reuse it on 50 different pages. I was also able to place it on the page in such a way that I could include it under the Title of the page and even iinsert an indiviual banner above the header.shtml. Will I be able to do basically the same thing with Dreamwaver 5.5s header and footer function? If so, is there anything special I need to be aware of?

I guess I didn't quite explain myself as well as I should have.
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How can I use a dll if I dont have a header file

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I have a C++ header file that contains around 2000 preprocessor directives:
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kaycea114 wrote:
Hi,
Where do you think I should use the string?
The way that getOffset is currently defined in the DLL, I have to connect an integer input into the LabVIEW function. This prevents me from entering in: MEM_1 as the input to the LabVIEW function.
Are you suggesting that I change getOffset to receive a String parameter ("MEM_1")? Does that mean I need to do a string compare (line by line) through the header file to get the offset? It seems like doing this search through the header file would degrade performance, but if that's the only work around, then I'll do it.
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Attachments:
XMLfile.doc ‏135 KB
XMLfile.doc ‏135 KB

Place function in header file?

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