An implementation may provide any or all of the feature identifiers listed below for use by cond-expand and features, but must not provide a feature identifier if it does not provide the corresponding feature.
r7rsAll R7RS Scheme implementations have this feature.
exact-closedThe algebraic operations +, -, *, and expt where the second argument is a non-negative integer produce exact values given exact inputs.
exact-complexExact complex numbers are provided.
ieee-floatInexact numbers are IEEE 754 binary floating point values.
full-unicodeAll Unicode characters present in Unicode version 6.0 are supported as Scheme characters.
ratios/ with exact arguments produces an exact result when the divisor is nonzero.
posixThis implementation is running on a POSIX system.
windowsThis implementation is running on Windows.
unix, darwin, gnu-linux, bsd, freebsd, solaris, ...Operating system flags (perhaps more than one).
i386, x86-64, ppc, sparc, jvm, clr, llvm, ...CPU architecture flags.
ilp32, lp64, ilp64, ...C memory model flags.
big-endian, little-endianByte order flags.
<name>The name of this implementation.
<name-version>The name and version of this implementation.