Porting newlib.

Paul Chavent paul.chavent@free.fr
Sat Jan 8 08:59:00 GMT 2005

Good morning.

I have some questions about porting Newlib. It seems that for a new 
platfrom support we typicaly need :
  - a linkscript (no deal with newlib, but with binutils/ld)
  - a start code and syscalls implementation (that must be provided for 
  - some other thing ?

Moreover, your online doc on libc tells us to implement a minimum set of 
syscalls. For example _exit close etc...
In this doc, some function begin with an underscore and other not.
In the syscall.c and libcfunc.c (in the newlib/libc/sys/arm directory) 
it is explain :
   - Functions which begin with an underscore are in the system 
namespace and go in the syscall.c file.
   - Functions without leading underscore are in the C namespace and go 
in the libcfunc.c file.

I don't understand the difference between the system namespace and C 
namespace and my questions are :
  Are system namespace and C namespaces equivalent to user space and 
kernel space in the Linux kernel ?
  Which minimum syscalls should we provide : with underscore or without ?
  If we provide some underscore functions, should we provide the sames 
without underscore ?

Ok, a last thing : in the newlib/configure.host there is
	if [ "x${newlib_may_supply_syscalls}" = "xyes" ] ; then
and in newlib/libc/sys/arm/Makefile.am :
   extra_objs = syscalls.o
   extra_objs =
   lib_a_SOURCES = libcfunc.c trap.S

The facts :
   If newlib may not supply syscalls, the sys_dir is not set and neither 
syscalls.c or libcfunc.c are used.
   If newlib may supply syscalls either syscalls.c and libcfunc.c are used.
The question :
   Is there any case where syscalls.c is used and libcfunc is not or the 
oposite ?

Thank you.


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