nuttx

History

Gregory Nutt 419c4cb6be A little more progress toward the implementation of per-window framebuffers. Still missing: - Logic that generates the low lever framebuffer renderers for the per-window framebuffers, - The logic that picks off the per-window framebuffer updates from normal graphics device updates. This logic must update both the per-window framebuffer and the graphics device (from the framebuffer). Squashed commit of the following: graphics: Add logic to allocate the per-window framebuffer. graphics: A few fragmentary thoughts on how a per-window framebuffer could be represented and allocated.		2019-03-14 11:20:14 -06:00
..
libc	lib_gethostbyaddrr.c edited online with Bitbucket	2019-03-11 03:55:08 +00:00
libdsp	Merged in raiden00/nuttx_pe (pull request #771 )	2018-12-02 11:49:25 +00:00
libnx	A little more progress toward the implementation of per-window framebuffers. Still missing:	2019-03-14 11:20:14 -06:00
libxx	libs/libxx/Kconfig: utomatically select CONFIG_LIBC_WCHAR and CONFIG_TIME_EXTENDED when CONFIG_LIBCXX is selected since libcxx compile fails if without these two option	2019-01-27 07:00:07 -06:00
README.txt	Remove trailing spaces at the end of lines.	2018-08-13 07:39:38 -06:00

README.txt

README
======

This directory holds NuttX libraries.  Libraries in NuttX are very special
creatures.  The have these properties:

1. They can be shared by both application logic and logic within the OS when
   using the FLAT build.

2. But in PROTECTED and KERNEL modes, they must be built differently:  The
   copies used by applications and the OS cannot be the same.  Rather,
   separate versions of libraries must be built for the kernel and for
   applications.

3. When used by the OS, some special care must be taken to assure that the
   OS logic does not disrupt the user's errno value and that the OS does
   not create inappropriate cancellation points.

   For example, sem_wait() is both a cancellation point and modifies the
   errno value.  So within the FLAT build and without kernel version for
   the PROTECTED and KERNEL builds, the special internal OS interface
   nxsem_wait() must be used.  Within libraries, the macro  _SEM_WAIT()
   (as defined in include/nuttx/semaphore.h) is used instead.  The
   definition of this macro accounts for the different usage environments.

NOTE:  The libraries under libs/ build differently from other NuttX
components:  There are no build-related files in the libs/ directory; it
is simply a container for other well-known, individual library directories.
The upper level Makefile logic is aware of the libraries within the libs/
container.

The only real function of the libs/ directory is to prevent the top-level
directory from becoming cluttered with individual libraries.