Overview

This table indicates which of the POSIX.1 functions (as listed in the Open Group Single Unix Specification) are supported on MacOS X (gcc 3.3), Linux (gcc 3.2.2),  Microsoft Windows Runtime Library (MS Visual C++ 7.0 .NET), Cygwin, MingGW, and NSPR 4.3.  For MacOS X, Cygwin, MinGW and Linux, the list was generated by searching header files for the functions that are defined in the specification. To get the list of Microsoft Windows Runtime Library functions, the Runtime Library documentation posted on MSDN was consulted. The Cygwin online documentation was also used to complete the Cygwin list.

The Single Unix Specification groups together some of the functions, for example execl, execvp, etc. are described under the heading "exec", and so the list of functions in the specification is actually larger than what is presented in this table. Still, there are over 800 entries in the table, and is complete in the sense that all of the functionality of the Single Unix Specification is represented here.

The NSPR 4.3 column attempts to identify the functions in NSPR that provide a similar capability to the POSIX.1 interface, although using a different syntax that defined by POSIX.1. Where support for a given interface is not provided on MacOS X, MS Windows, and Linux, then the NSPR function, if one is supported, may provide an acceptable solution. The NSPR functions not in green may also be applicable for ports outside of the three platforms this table focuses itself upon.

Functions that exist on all three platforms are identified with green background in the Function column. Interfaces that are not available everywhere but have a solution in NSPR are identified with a green background color in the NSPR 4.3 column.

In some cases, Microsoft C++ Runtime library defines a function that has the same name as the POSIX function, prefixed with one or more underscore ('_') characters. For example, _open(), _read(), _write(), and _close(), corresponding to the POSIX.1 functions open(), read(), write(), and close() respectively. Since the names are not portable due to the prefixed underscores, not to mention they may accept different arguments and may have different semantics than defined by the POSIX standard, I have opted to not flag the corresponding functions with a green background in the Function column. In the case where there exists an NSPR equivalent (or C++ functionality, say iostreams, or perhaps functionality from some other library, such as Boost), use of the equivalent is preferred since 1) the API is the same across platforms 2) the semantics are the same across platforms. If not portable alternative exists, wrapping the function on all platforms and calling the wrapper function is perhaps the best alternative, as long as care is taken to ensure that the wrapper only exposes (and promises) functionality present across all platforms.

Related Links

Unix98 API tables
Unix03 (Single Unix Specification) API tables