Hi Greg, Thanks for this; it is one of the greatest features you have built into NuttX - POSIX compliance!!!
I have a few programs which compile either for NuttX or Linux/MacOS with no changes (or Makefile -D options). I started out that way, using -D__NuttX__ but then found that besides the includes for NuttX, almost all of the std c library and some of sys (at least filesystem/serial code) needs no change! Instead of gcc dumpspecs archaeology, I just did the opposite and have NuttX be the fall-out for conditional includes in the Posix environment. Most NuttX/Linux cross-platform code files have the below: #ifndef __linux__ #include <nuttx/config.h> /* NuttX */ #endif /* POSIX Includes (Linux/Nutt-X) common */ #include <stdint.h> #include <stdio.h> #include <string.h> #include <fcntl.h> #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <pthread.h> #include <math.h> #include <unistd.h> #include <dirent.h> #include <sys/ioctl.h> #include <stdlib.h> #include <sys/types.h> #include <sys/stat.h> #include <sys/statfs.h> #include <sys/ioctl.h> #include <sys/mount.h> #include <stdbool.h> #include <errno.h> #include <time.h> I also found some mutually exclusive cases like the below: #ifdef __linux__ /* Linux include -D__linux__ */ #else /* Nutt-X include -D__NuttX__ */ #endif And yes, I found __NuttX__ defined in the past also $find . -type f | xargs grep _NuttX__ ./nuttx/configs/stm32f4discovery/testlibcxx/Make.defs: -D__NuttX__ ./nuttx/configs/bambino-200e/netnsh/Make.defs:CXXFLAGS += $(ARCHDEFINES) $(EXTRADEFINES) -pipe -std=c++11 -DCLOCK_MONOTONIC -D__NuttX__ ./nuttx/configs/imxrt1050-evk/libcxxtest/Make.defs: -D__NuttX__ $ Of course if you're targeting more than one RTOS you'll need more, but I have had great luck with filesystem, pthread, mutex, and serial (termios) portability. Thank you -James On Tue, Feb 22, 2022 at 5:11 PM Gregory Nutt <spudan...@gmail.com> wrote: > Hmm.. but that doesn't help with setting up the build. That definition is > only visible to C code since it is a C pre-processor definition defined in > the CFLAGS. It can't really be used to customize the build, at least not > in any clean way. > > It would have been useful to have a similar, Make=friendly definition as > well. > > On Tue, Feb 22, 2022 at 7:03 PM Gregory Nutt <spudan...@gmail.com> wrote: > > > Thanks! Now I see it defined tools/Config.mk. Looks like that was added > > with #2192. That is exactly what I need! > > > > I was thrown off because there are applications that ARE using __NUTTX__: > > > > $ grep -rl __NUTTX__ * > > system/adb/Makefile > > system/libuv/0001-initial-libuv-port-to-nuttx.patch > > system/libuv/libuv/Makefile > > system/libuv/tests/Makefile > > > > There are a couple using __NuttX__, but didn't catch those: > > > > $ grep -rl __NuttX__ * > > netutils/ftpd/ftpd.c > > netutils/webclient/webclient.c > > > > Thanks again. > > > > > > > > On Tue, Feb 22, 2022 at 6:43 PM Nathan Hartman <hartman.nat...@gmail.com > > > > wrote: > > > >> On Tue, Feb 22, 2022 at 2:14 PM Gregory Nutt <spudan...@gmail.com> > wrote: > >> > >> > One option would be to define __NUTTX_ in tools/Config.mk instead of > in > >> > each individual apps/Makefile. That would provide a single point > >> > definition coordinate all usage. > >> > >> > >> Just one (possible) correction: IIRC it is capitalized as __NuttX__. All > >> my > >> cross platform applications look for __NuttX__ to detect that they are > >> being built this way. The buildroot toolchain does define that, though I > >> am > >> *not* using the buildroot toolchain and it is somehow defined anyway. I > am > >> away from my computer at the moment so I cannot check where it is coming > >> from, but from memory I think we added something to the NuttX build > >> scripts > >> some time ago (maybe about 1 or 2 years ago) to cause that to be defined > >> with all compilers. (Or perhaps I remember wrong and I added it to our > >> in-house boards' Make.defs.) > >> > >> Nathan > >> > > >
