version() abuse! Note of library writers.

[Anders F Björklund]

Travis Boucher wrote:
> The use of version(...) in D has the potential for some very elegant 
> portable code design.  However, from most of the libraries I have seen, 
> it is abused and misused turning it into a portability nightmare.

It has done this for years, so it's already turned that way.
Usually it's "version(Win32) /*Windows*/; else /*linux*/;"...

> Anything that accesses standard libc functions, standard unix semantics 
> (eg. signals, shm, etc) should use version(Posix) or version(unix).

Nice rant, but it's "version(Unix)" in GCC and we're probably
stuck with the horrible version(linux) and version(OSX) forever.

> Build systems and scripts that are designed to run on unix machines 
> should not assume the locations of libraries and binaries, and refer to 
> posix standards for their locations.  For example, bash in /bin/bash or 
> the assumption of the existence of bash at all.  If you need a shell 
> script, try writing it with plain bourne syntax without all of the bash 
> extensions to the shell, and use /bin/sh.  Also avoid using the GNU 
> extensions to standard tools (sed and awk for example).  If you really 
> want to do something fancy, do it in D and use the appropriate {g,l}dmd 
> -run command.

I rewrote my shell scripts in C++ for wxD, to work on Windows.
Tried to use D (mostly for DSSS), but it wasn't working right.

> A few things to keep in mind about linux systems vs. pretty much all
> other unix systems:

Nice list, you should put it on a web page somewhere (Wiki4D ?)
Usually one also ends up using runtime checks or even autoconf.

--anders


PS. Some people even think that /usr/bin/python exists. :-)
     Guess they were confusing it with standard /usr/bin/perl