RTEMS and newlib problems

[Denny.Bai]

i am in struggling with the RTEMS  and newlib problems..

i am porting RTEMS to arm platform. but  when i compile the
hello_world example,  printf function doesn't work. but if i use
printk function , the Terminial will receive the data.

    and when i check the rtems source code about the interface between
the rtems and newlib,  i find the newlib function _open() is not
called. and when i printk the values of the
libc_global_reent._stdout->write and the 
libc_global_reent._stdout->read, output values both are zero.

   BTW: what does the macro RTEMS_NEWLIB mean?

   is there libc_init() function's problem?
   anybody who can tell me what should i do? Thank a mil!

--
Bai.Shaolin
Northeastern  University,LiaoNing,China