+Minix 3.1.8, AIX 5.1, HP-UX 11, Solaris 9.
+@item
+This function is only defined as a macro with arguments on some platforms:
+MSVC 9.
+@end itemize
+
+Portability problems fixed by Gnulib module @code{floorf-ieee}:
+@itemize
+@item
+This function returns a positive zero for a minus zero argument
+on some platforms:
+OSF/1 5.1.