ISO C features missing from microlib

All functions dealing with wide characters or multibyte strings are not supported by microlib. A link error is generated if these are used. For example, mbtowc(), wctomb(), mbstowcs() and wcstombs(). All functions defined in Normative Addendum 1 are not supported by microlib.

All functions that interact with an operating system are not supported by microlib. For example, abort(), exit(), atexit(), clock(), time(), system() and getenv().

All the stdio functions that interact with a file pointer return an error if implemented. The only exceptions to this are the three standard streams stdin, stdout and stderr.

The default C locale is the only one available.

The functions signal() and raise() are provided but microlib does not generate signals. The only exception to this is if the program explicitly calls raise().

Floating point support is not IEEE 754 compliant.

Operations that produce unpredictable output are those that:

Additionally, the sign of zero is not treated as significant by microlib and produces unpredictable output.

Microlib has no re-entrant variant. Microlib does not provide mutex locks to guard against code that is not thread safe. Use of microlib is not compatible with RWPI compilation modes, and although ROPI code can be linked with microlib, the resulting binary will not be ROPI-compliant overall.