nuttx

History

Gregory Nutt a64869aa67 CONFIG_NFILE_DESCRIPTORS=0 can no longer be used to disable the file system. NuttX with no file system does not make sense. Squashed commit of the following: configs/: The few configurations that formerly set CONFIG_NFILE_DESCRIPTORS=0 should not default, rather they should set the number of descriptors to 3. fs/: Remove all conditional logic based on CONFIG_NFILE_DESCRIPTORS == 0 tools/: Tools updates for changes to usage of CONFIG_NFILE_DESCRIPTORS. syscall/: Remove all conditional logic based on CONFIG_NFILE_DESCRIPTORS == 0 libs/: Remove all conditional logic based on CONFIG_NFILE_DESCRIPTORS == 0 include/: Remove all conditional logic based on CONFIG_NFILE_DESCRIPTORS == 0 drivers/: Remove all conditional logic based on CONFIG_NFILE_DESCRIPTORS == 0 Documentation/: Remove all references to CONFIG_NFILE_DESCRIPTORS == 0 binfmt/: Remove all conditional logic based on CONFIG_NFILE_DESCRIPTORS == 0 arch/: Remove all conditional logic based on CONFIG_NFILE_DESCRIPTORS == 0 net/: Remove all conditional logic based on CONFIG_NFILE_DESCRIPTORS == 0 sched/: Remove all conditional logic based on CONFIG_NFILE_DESCRIPTORS == 0 sched/Kconfig: CONFIG_NFILE_DESCRIPTORS may no longer to set to a value less than 3 configs/: Remove all settings for CONFIG_NFILE_DESCRIPTORS < 3		2019-02-11 12:09:26 -06:00
..
libc	CONFIG_NFILE_DESCRIPTORS=0 can no longer be used to disable the file system. NuttX with no file system does not make sense.	2019-02-11 12:09:26 -06:00
libdsp	Merged in raiden00/nuttx_pe (pull request #771 )	2018-12-02 11:49:25 +00:00
libnx	Cosmetic updates from review of last PR.	2018-11-12 09:43:33 -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.