Lee Rhodes writes: > > "Andrew Haley" wrote: > > > > Yes, there is. > > > > Endianness, like hundreds of other environment quersies needed at > > compile time, is handled by GNU Autoconf. There's nothing special > > about endianness: it's just another property of the environment you're > > compiling for. > > Thanks for pointing me to Autoconf. I haven't used Autoconf, but I > will now have to study it. Nonetheless, the Macro AC_C_BIGENDIAN > appears to only check for the big endian case, the tacit assumption > being that if it ain't big it must be little. But what about the > PDP/ARM case? Or is it's weird layout no longer supported by GCC? AC_C_BIGENDIAN is for integers. As far as I am aware the PDP/ARM "middle-endian" problem only applies to floating-point words, and the situation for those is far more complex than mere endianness. Not every platform supports the IEEE-754 format, and picking apart other formats requires special-case programming. Happily, this isn't a problem that most people have to solve. I mostly agree with Nick, by the way: in most cases it's best to use standard portable code internally and only do endian conversions at I/O boundaries. This is the approach taken by the htonl() family of functions. It's very rare that anyone really needs to do anything that needs to know the endianness of a machine. (Of course, I don't know what problem you're trying to solve, so I'm not saying that *you* don't need to do something that needs it.) Andrew.
