Thread-safeness of API functions

[Joris van Rantwijk]

Hello,

I have a few questions about thread-safeness of the RTEMS API.

Are all functions in the C and POSIX API reentrant (except for the well 
known unsafe functions such as gmtime() and strtok()). For example, is 
it safe when two tasks concurrently call fprintf() for two different 
file descriptors?

Is it also safe if two tasks concurrently call printf() for the *same* 
file descriptor?

POSIX.1c seems to guarantee that this is safe ("man 3p flockfile").
In the source code of newlib, I see that indeed vfprintf() internally 
calls flockfile(). However flockfile() itself is not implemented either 
in newlib or in RTEMS. So it seems that concurrent calls to printf() for 
the same file descriptor are dangerous and could potentially crash the 
application. Is that true?

I have the same questions about sockets. For example, is it safe to 
concurrently call connect() for different sockets?
Is it safe to concurrently call sendmsg() for the same socket?

Please help me out. I can not find this in the documentation.

Greetings,
 Joris.