Re: a question about libc printf

[Carl Miller <chaz at energoncube dot net>]

> Hi,
>     I am not quite sure this is the right mailing list for my question,
> but this is the only list I know about newlib.
>     I am porting newlib to a ppc405 based board and implementing some libc
> hooking up routines like write(). In write() I call a UART driver to print
> out a string, but it seems that printf() has some buffering mechanism
> built in, so if I call printf("hello \n") ir works; but if I call
> printf("hello "), there is nothing coming out.
>    Could you point me which tricky point I missed?
>
> thanks a lot.

You might try reading the man pages for the fflush() and setvbuf() C
library functions.

These functions, as well as the way printf is behaving, are mandated by
the POSIX.1a spec, so all POSIX-compliant standard C libraries should
behave the same way.  (Mentioned only because I've never worked with
newlib, but I know the glibc, as well as Linux's older libc4 and libc5,
implementations of these functions conform strictly to POSIX.)


                               ------Carl 

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