I'm using Linux Ubuntu and compiling with G++ 4.8.2 if that helps
I've been playing around with creating my own header files, trial and error and reading online. I've run into something that's really confusing me:
Example 1 (this works):
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//myheader.h
#pragma once
int myfunction();
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//myheader.cpp
#include"myheader.h"
int myfunction()
{
// do whatever
return aVariable;
}
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//main.cpp
#include"myheader.h"
int main()
{
int a = myfunction();
}
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compile by running command:
And it works perfectly
Example 2 (this is where I'm confused):
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//myheader.h
#pragma once
int myfunction();
int myotherfunction();
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//myheader.cpp
#include"myheader.h"
int myfunction()
{
// do whatever
return aVariable;
}
int myotherfunction()
{
// do whatever
return anotherVariable;
}
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//main.cpp
#include"myheader.h"
int main()
{
int a = myfunction();
int b = myotherfunction();
}
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Compile by running command:
And I get an compiler error about undefined references to the functions.
However, if I compile by using
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g++ main.cpp myheader.cpp
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it compiles and works as expected.
Why do I not need to add the header source file in the g++ compile command if there's only one function, but it needs it if I have more than one function?
Is there a way to do this, using multiple functions in the header, where I don't have to compile the source file along with my regular code?
Am I just totally missing the point of headers (very possible)?
Thanks so much to anyone who can shed some light on this for me.
