LF Tip: #defines for writing portable C-code
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SoftwareDevelopment
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original in en Guido Socher
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Introduction
Java is known as "write once works never" and C is "write once, compile
and works always". In other words C code is very portable and the beauty
is also that you can have preprocessor #ifdef statements to distinguish between
the different platforms. This way you have just one piece of code which
can be recompiled on different systems even without running an
auto configuration script before compilation.
Here is an example:
#ifdef sun
// solaris
static char *port="/dev/ttya";
#endif
#ifdef linux
// linux
static char *port="/dev/ttyS0";
#endif
What #define is available?
The question is only how do you know that there is a #define linux or __linux__?
... and what other #defines do we have?
It's quite simple. Just run this command and you get a list of
pre-defined #define statements:
touch /tmp/foo.h ; cpp -dM /tmp/foo.h
That's all.