How to link against newlib?
Mon Jul 9 21:54:00 GMT 2012
On 06/29/2012 06:12 PM, Christian Haake wrote:
> Hi there,
> this is my first post so I apologize if my question is a duplicate...
> Currently I'm trying to implement the sbrk() system call which is used
> by malloc. For this in the syscalls.c file I included a header file
> called pagealloc.h.
> But while compiling I get a "undefined reference" error because the
> associated object file will not be linked.
> So my question is how to tell newlib which object file to link with.
> Should I customize a Makefile and if yes, which one and how?!?
> Thanks in advance for your help.
You're going to have to elaborate a lot more.
What platform are you configuring for? Are you adding a new platform
and if so, did you create a libgloss library?
For new platforms, it is recommended you create a libgloss library to
You have some choices after that. A number of platforms provide an ld
script in libgloss which knows how to link a particular libgloss
library. That makes it easy to compile/link - the -T option of gcc is
used to specify the name of the ld script.
See the libgloss/mn10300 directory for an example of an ld script that
is set up for a simulator (sim.ld).
If your compiler builds multi-libs, then the newlib build will build
multiple versions of the libraries with different options. It is
recommended you link the newlib/libgloss directories into your gcc
check-out and make them siblings of the gcc directory so you can
build/install gcc, newlib, and libgloss together. When you compile/link
with that gcc, it will automatically figure out the path to the
multi-libs that are appropriate for the gcc options you have chosen.
Otherwise, you can manually specify the path to the appropriate
libgloss/newlib libraries but that is more difficult.
See the newlib FAQ found at sourceware.org/newlib for pointers on
porting and a link to the crossgcc FAQ.
-- Jeff J.
More information about the Newlib