Changes between Version 1 and Version 2 of PortingSoftware

Timestamp:

2014-03-06T17:46:31Z (11 years ago)

Author:

Vojtech Horky

Comment:

WIP - libposix

PortingSoftware

@@ -11 +11 @@
  * [https://github.com/vhotspur/coastline Coastline] - scripts for porting POSIX-like software to HelenOS (and some [http://vh.alisma.cz/blog/2013/03/30/introducing-helenos-coastline blog] [http://vh.alisma.cz/blog/2013/12/08/helenos-coastline-updates-status-matrix posts])
  * Python porting: [https://github.com/zhalas/helenos-build-python repository] and [http://lists.modry.cz/private/helenos-devel/2013-April/006421.html ML announcement]
+
+== POSIX emulation layer ==
+
+HelenOS is not [wiki:DiffFromUnix another Unix-like OS] and thus it needs an emulation for applications that were written for Unix systems.
+This emulation is currently in HelenOS provided by `libposix` library that provides implementation of functions that are part of POSIX standard but were considered inappropriate for HelenOS.
+
+`libposix` provides an (incomplete) illusion that the application has access to standard POSIX headers and functions.
+The ported application is then linked with `libposix` which translates the calls to HelenOS specific implementations in `libc`.
+
+//Implementation detail//: some of the functions in `libc` have the same name as standard POSIX ones or they offer slightly different behaviour.
+To prevent naming clashes, symbols in `libc.a` are renamed to avoid the need to rename the POSIX versions (which was an older approach where renaming was done during preprocessing, however this approach has various disadvantages).