@item
This function is missing on some platforms:
Minix 3.1.8, AIX 5.1, HP-UX 11, Solaris 9, mingw, MSVC 9.
+@item
+This function produces wrong results for arguments <= -17.32868 on some platforms:
+IRIX 6.5.
@end itemize
Portability problems not fixed by Gnulib: