Cleaning up FILE in stdio..

[John Baldwin]

Way back in the 4.x days we had a fiasco over changing the size of FILE 
(struct __sFILE) to add locking for multithreaded apps because 
the 'stdin', 'stdout', and 'stderr' symbols were direct references to the 
global array of FILE objects.  The first fix was to move the locking fields 
into a private 'struct __sFILEX' to preserve the size of FILE.  Later the 
stdin/out/err symbols were fixed to reference standalone pointers instead of 
the global array.  Given that, I think at this point we can safely merge 
__sFILEX back into __sFILE w/o breaking anything.  This is assuming that the 
contents and layout of FILE are not a public ABI (i.e. we malloc the things 
internally and consumers should just treat the pointer value as a cookie and 
not grub around in the internals).  In addition to removing the __sFILEX 
stuff, I'd like to change the fd member of FILE to be an int so you can open 
more than 32k files via fopen().  Otherwise, if fopen() gets an fd that is > 
SHORT_MAX, it gets sign extended when the fd is passed to read(), close(), 
etc. and those calls fail with EBADF.

Comments?

-- 
John Baldwin