(Not to be confused with calculator linking)

I am currently developing two big projects, one public and one secret! They are both C based, and are very exciting to develop!
However... there are always concerning linking problems! The code can be perfectly valid, but it will never compile/link! There are also some interesting features that I would like to see in ndless, which if possible, I'd like to help with.

That said, here are some things that I would like to get fixed:
1) Standard C Library Collisions (or undefined references!)
This applies to both projects, though the public one's error messages were shorter and probably easier to fix:
nspire-ld obj/*.o -L./nrgbsdk/lib -lRGB -lgcc -nostdlib -lc -lm -o nrgbwabbit
/usr/local/arm/lib/gcc/arm-none-eabi/4.6.3/../../../../arm-none-eabi/lib/libc.a(lib_a-svfscanf.o): In function `__ssvfscanf_r':
/home/albert/ndless/modern_toolchain/build/arm-none-eabi/newlib/libc/stdio/../../../../../newlib-1.20.0/newlib/libc/stdio/vfscanf.c:1584: undefined reference to `__aeabi_d2f'
/usr/local/arm/lib/gcc/arm-none-eabi/4.6.3/../../../../arm-none-eabi/lib/libc.a(lib_a-syscalls.o): In function `_sbrk':
/home/albert/ndless/modern_toolchain/build/arm-none-eabi/newlib/libc/sys/arm/../../../../../../newlib-1.20.0/newlib/libc/sys/arm/syscalls.c:499: undefined reference to `end'
/usr/local/arm/lib/gcc/arm-none-eabi/4.6.3/../../../../arm-none-eabi/lib/libc.a(lib_a-strtod.o): In function `strtof':
/home/albert/ndless/modern_toolchain/build/arm-none-eabi/newlib/libc/stdlib/../../../../../newlib-1.20.0/newlib/libc/stdlib/strtod.c:1194: undefined reference to `__aeabi_d2f'
collect2: ld returned 1 exit statusThis does NOT link to the standard library and instead depends on the ndless syscalls and definitions. However, this causes problems, as seen above. When linking with the standard library, it ends up having multiple definition errors instead. Maybe there could be a define allowing the use of newlib instead?

2) New feature: ELF loader with dynamic libraries support
BFLT does *not* implement this at all. Only ELF can load dynamic libraries on the fly (dlopen, dlsym, etc.). This would be very useful for plugin support in my secret project, which works but is very limited without ELF support.

3) Multithreading
This may or may not be needed for SDLWabbitemu, but it would be nice to have. tangrs I believe made a proof of concept, and NUCLEUS OS indicates support for it. (Maybe there's a syscall out there?)

4) Secret project with secret changes requested to disable something with a define. (ExtendeD knows what I'm referring to - I am willing to create the patches for that if you don't have time!)

Thanks in advance!

ELF is very complicated. tangrs had made an ELF loader, but ELF files could be overly big in some simple cases.

Yes indeed... but dynamically loading libraries is essential for any application that depends of plugins written in C.
I guess what I'm asking for is some implementation of dlopen(), dlsym(), and dlclose() for BFLT.

And Nucleus is indeed a multi-threaded RTOS.

Yup, as I thought: http://www.mentor.com/embedded-software/nucleus/kernel

1) Try to remove the -nostdlib switch and any #include directive for the standard headers. Conflicts between newlib and os.h are an Ndless design flaw, sorry about that.

In the end, this is what I did:
 - open Ndless-SDK/ndless/system/ldscript and add end = .;
 - open Ndless-SDK/ndless/system/osstub.c and comment out void _exit(void) { exit(-1); } and rebuild Ndless
 - build the object files with -nostdlib
 - at linking, remove -nostdlib
It builds successfully, but it doesn't load at all (and crashes)! Not sure what is happening now... I guess I'll have to find a way to hook up GDB to the nspire_emu.

3) This may only be a matter of exporting the pthreads definition from the OS (for example phtread_create() an pthread_join() have already be found: https://www.unsads.com/scm/svn/nsptools/symbols/trunk/OS_cascx-3.1.0.idc [guest/guest]).
But the OS clock cursor will once again annoy us since interrupts must be able for these functions to work.

Ah, interesting! I would assume that there would be more API functions that are hidden (like pthread_exit()), of course. And for the OS clock cursor, are you referring to the startup screen? Is there no way to disable that?

As always, thank you for your help!

Although it's just a matter of setting a simple OS switch. Ndless really requires developers to help me handle all these requests, I can't do it alone anymore.

- open Ndless-SDK/ndless/system/osstub.c and comment out void _exit(void) { exit(-1); } and rebuild Ndless

What is this one for?

It builds successfully, but it doesn't load at all (and crashes)! Not sure what is happening now...

Using newlib functions is not recommended as long as tangr's bFLT loader hasn't been merged into Ndless, since some of these functions require relocation, and you can't guess which ones.

I guess I'll have to find a way to hook up GDB to the nspire_emu.

This one is also at the top of the TODO list.
Lionel Debroux has already merge my GDB stub into the latest (but not released publicly?) update of nspire_emu. I'll do some non-regression tests on Ndless and update the SDK with it as soon as possible.

Once again sorry for the delay. Fill free to contribute a way or another to all these tasks, I can give update rights to the repository to anyone I trust willing to contribute if needed.

Maybe an external Git repository, containing a mirror of the SVN as the main branch and experimental branches ?

I've set up a Google Code repository for Ndless!
http://code.google.com/p/ndless/

I've also set up a branch for one of my own changes. The tree can be found here and changes here.