@itemize
@item
This function is missing on some platforms:
-MacOS X 10.3, OpenBSD 3.8, mingw.
+Mac OS X 10.3, OpenBSD 3.8, mingw, MSVC 9.
+@item
+This function can hang if it stats all preceding
+entries in /proc/mounts, and any of those file systems
+are hard-mounted and not available. This affects
+Linux < 2.6.36.
+@item
+On platforms where @code{f_blocks} in @samp{struct statvfs} is a 32-bit
+value, this function may not work correctly on files systems larger than
+4 TiB. The fix is to use the @code{AC_SYS_LARGEFILE} macro. This affects
+glibc/Hurd, HP-UX 11, Solaris.
@end itemize
Gnulib provides a module @code{fsusage} that provides similar information