@node logb
@subsection @code{logb}
@findex logb

POSIX specification:@* @url{https://pubs.opengroup.org/onlinepubs/9799919799/functions/logb.html}

Gnulib module: logb or logb-ieee
@mindex logb
@mindex logb-ieee

Portability problems fixed by Gnulib:
@itemize
@item
This function is missing on some platforms:
Minix 3.1.8, MSVC 9.
@item
This function is missing a declaration on some platforms:
Cygwin 1.5.x.
@item
This function produces wrong results for subnormal numbers on some platforms:
glibc 2.17/ppc, glibc 2.7/sparc, glibc 2.7/hppa, Solaris 11.4, Cygwin 1.5.x.
@end itemize

Portability problems not fixed by Gnulib:
@itemize
@end itemize
