header files and multiple files

Hi

I'm tring to learn how to write a program with multiple files.
I have a working program composed by a file main.c with many functions inside. I've tried to put one function outside.
I mean that now i have:

1) main.c ( with the #include " function1.h" and where i call the function1),
2) funtion1.c ( with the #include " function1.h", and where I write what the function1 do),
3)function1.h (where all i do is just to declare the function1)

but now the program doesn't not compile and i get the linker error:

Code:

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/main.c:32: undefined reference to `function1'
collect2: ld returned 1 exit status

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Anyone can help?

Thanks

D.

looks like you're working with visualC.
Add the .c file to your project.

Sorry I'm not sure to understand.
Do you mean to add function1.c in the same directory of main.c? it already is.

thx

No, you need to tell your linker that you are linking more than one source file together. Just having a source file wherever it may be does not mean the linker understands that it needs to be combined with any others to produce a complete executable. Typically, with IDEs you create a project and add all your source files to that project, then when the compiler/linker is called it knows to compile and link everything together.

What compiler/IDE are you using?

yes you are right.

I use gcc.

I've done it !, just telling it to gcc in the line command.

Thx
D.

Quote:

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Originally Posted by Dedalus

I use gcc.

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Okay you have something backward then, consider:

Quote:

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1) main.c ( with the #include " function1.h" and where i call the function1),
2) funtion1.c ( with the #include " function1.h", and where I write what the function1 do),
3)function1.h (where all i do is just to declare the function1)

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Hmmm...looks like niether main.c nor function1.h include function1.c


Persuming you just want to go "gcc main.c", what you should have is:

1) main.c with #include "function1.h"
2) function1.h with #include "function.c"
3) function1.c doesn't need to include anything.

But I would just combine function.c into function1.h anyway. You can put more than just prototypes into an .h file. Then there will be just one include file. Simple enough?