On Wed, Apr 23, 2014 at 9:14 AM, Grant Edwards <grant.b.edwa...@gmail.com> wrote: > On 2014-04-22, DJ Delorie <d...@redhat.com> wrote: >> >>> I was surprised to see DJ's comment that there actually was no >>> standard system interface; the "standard interface" I was referring to >>> is the one documented at http://neptune.billgatliff.com/newlib.html >> >> "The key to a successfully ported newlib is providing stubs that >> bridge the gap between the functionality newlib needs, and what your >> target system can provide." >> >> This bridge is what I was referring to. Newlib calls read() but does >> not provide an implementation of it. Libgloss provides various >> target-specific implementations of read(), the one I wrote for msp430 >> uses CIO to communicate with the simulator/debugger. > > Why is newlib calling read(), and from what is it expecting to read? > >>> I was expecting for MSP430 to also simply implement the functions >>> stubbed in newlib's libnosys, but at first glance it looks like the >>> CIO one uses different names, and maybe doesn't support all the same >>> functions. >> >> Hmmm... it should be all the same names. I only changed the existing >> libgloss hooks. But, I don't always do all the hooks, usually only >> write() and exit() are needed for our testing. > > Again, why should newlib be calling write() and what is it expecting > to write _to_? > > What does it expect exit() to do?
Again: whatever the environment wants it to do. In my case, I'm using printf(3c) in my code, and I want it to output to one of the UARTs, which newlib accommodates by using write(2) to descriptor 1, just like any other standard C library. This works because I supply a _write() function that does that. Or maybe it sends the data to an LCD. Maybe exit() starts blinking a red LED if the return code isn't zero. Whatever any of the system functions do, it's my choice, and I like that newlib allows me that control. Peter ------------------------------------------------------------------------------ Start Your Social Network Today - Download eXo Platform Build your Enterprise Intranet with eXo Platform Software Java Based Open Source Intranet - Social, Extensible, Cloud Ready Get Started Now And Turn Your Intranet Into A Collaboration Platform http://p.sf.net/sfu/ExoPlatform _______________________________________________ Mspgcc-users mailing list Mspgcc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mspgcc-users
