CYGPKG_LIBM
Boolean
ISO standard floating point mathematical library containing many useful functions for mathematical calculations.
CYGPKG_LIBM_COMPATIBILITY
Dummy
These options deal with behavior related to the various compatibility modes - POSIX, IEEE, X/OPEN and SVID.
CYGSEM_LIBM_COMPAT_IEEE_ONLY
Radio
The math library can be hard-coded to only behave in one compatibility mode - IEEE. This cannot be changed at run-time. IEEE mode is the most minimal of the compatibility modes, and so this will best help code size and speed, as well as omitting the code for other compatibility modes. If not defined, the math library can be set at run-time to any of the supported compatibility modes.
CYGPKG_LIBM_COMPATIBILITY_DEFAULT
Radio
If you want to have support for more than one compatibility mode settable at run-time, rather than hard-coded IEEE mode, this component lets you choose which mode should be the default.
CYGNUM_LIBM_COMPATIBILITY_POSIX
Radio
This sets the default compatibility mode to POSIX
CYGNUM_LIBM_COMPATIBILITY_IEEE
Radio
This sets the default compatibility mode to IEEE
CYGNUM_LIBM_COMPATIBILITY_XOPEN
Radio
This sets the default compatibility mode to X/OPEN
CYGNUM_LIBM_COMPATIBILITY_SVID
Radio
This sets the default compatibility mode to SVID
CYGFUN_LIBM_SVID3_scalb
Boolean
SVID3 defined the scalb() function as double scalb(double, double) rather than double scalb(double, int) which is used by IBM, DEC, and probably others. Enabling this option chooses the (double, double) version. Note there is a function double scalbn(double, int) which is unaffected by this choice.
CYGSYM_LIBM_NO_XOPEN_SVID_NAMESPACE_POLLUTION
Boolean
If you do not want to use either the X/Open or SVID3 compatibility modes, you may want to define this option to reduce the chance of namespace pollution. This is particularly likely to occur here as these standards define symbols with names that often appear in applications, such as exception, DOMAIN, OVERFLOW, etc. If your application also used these names, it may cause problems.
CYGSEM_LIBM_USE_STDERR
Boolean
The SVID3 standard says that error messages should be output on the stderr console output stream. This option allows this ability to be explicitly controlled. However, this still only has an effect in SVID3 compatibility mode.