C detecting that I'm compiling for FreeBSD

[Bill Evans at Mariposa]

If, say, I'm compiling with gcc(1) under Linux, a section of code will compile if it looks like this:

#if __linux__
/* your ad here */
#endif

How do I do such conditional compilation for FreeBSD (other than inverting the __linux__ test)? I'm hoping the answer would apply equally to clang(1) and gcc(1).

And a related question: Is there a way (at least for clang(1), but preferably also for gcc(1) running under FreeBSD) to simply dump all symbols defined at compile time, so I can browse through those beginning with an underscore, and find the answer to the previous question for myself?

 

[usdmatt]

For the first question you might be able to use the __FreeBSD__ value as mentioned here -
https://www.freebsd.org/doc/en/books/porters-handbook/porting-versions.html

 

[Bill Evans at Mariposa]

One if by land, two if by sea. Port left, starboard right. Stalagmites go up, stalactites g down. __linux__ lower case, __FreeBSD__ mixed case. Got it!

 

[obsigna]

One if by land, two if by sea. Port left, starboard right. Stalagmites go up, stalactites ...

..., and echo "" | cc -E -dM -xc - gives you all defines, which you always wanted to know about, but were afraid to ask for, in the exact spelling.