In a message dated 3/3/00 4:46:49 AM Eastern Standard Time,
[EMAIL PROTECTED] writes:
> Hi
>
> I've taken a project created with "Palm C App" stationary, and converted it
> to a "Palm C++" stationary project.(i.e created a standard Palm C++
project,
> and replaced the default source files with those from my Palm C project)
> My project also includes a static library, which I created, that contains
> usefull Utility functions. When the compiler tried to link my app, I got
an
> error saying that one of the functions in my Utility library was undefined.
> Anyway to cut a long story short, I figured out that If do the following to
> my Utility libraries header file, then the error went away (I got this by
> looking at the Palm OS headers)
>
> #ifdef __cplusplus
> extern "C" {
> #endif
>
> foo FooBar(Bar bar);
> ... nextFunction();
> ....etc();
>
> #ifdef __cplusplus
> }
> #endif
>
> My question is, what is the significance of 'extern "C"
> functionPrototypes }'
'extern "C"' has the effect of preventing name mangling. Name mangling is
used by C++ compilers to allow function overloading and works by building in
the function's parameters and return type into the function name that the
linker goes by. You'll find that many third-party libraries use 'extern "C"'
because it is a way to ensure some independence from the compiler that you
are using because there is no standard for how a compiler implements its
mangling. For example, the mangled names generated by VC++ and Borland are
different and this is one reason why an exported class from a VC++ DLL
doesn't work with a Borland EXE (along with case sensitivity differences, I
think).
-Pete
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