FlexSpin C Include Path Not Finding Files

[RbtsEvrwhr-Riley]

Example:

testme.cpp
|- GCS_MAVLink
|-- GCS_MAVLink.h

testme.cpp

#include <GCS_MAVLink.h>
#include <propeller2.h>

"C:/flexprop/bin/flexspin" -2 -l --tabs=8 -D_BAUD=230400 -O2 -Wall --charset=utf8 -I "C:/flexprop/include" -I. "E:/robotseverywhere/navcom2/ardupilot/ardupilot/libraries/testme.cpp"
"C:/flexprop/bin/flexspin" -2 -l --tabs=8 -D_BAUD=230400 -O2 -Wall --charset=utf8 -I "C:/flexprop/include" -I"E:/robotseverywhere/navcom2/ardupilot/ardupilot/libraries/GCS_MAVLink" "E:/robotseverywhere/navcom2/ardupilot/ardupilot/libraries/testme.cpp"
"C:/flexprop/bin/flexspin" -2 -l --tabs=8 -D_BAUD=230400 -O2 -Wall --charset=utf8 -I "C:/flexprop/include" -I"E:/robotseverywhere/navcom2/ardupilot/ardupilot/libraries/GCS_MAVLink/" "E:/robotseverywhere/navcom2/ardupilot/ardupilot/libraries/testme.cpp"

All 3 generate:

error: Preprocessor errors:
E:/robotseverywhere/navcom2/ardupilot/ardupilot/libraries/testme.cpp:1: error: Can't open include file "GCS_MAVLink.h"
#include <GCS_MAVLink.h>
1 error in preprocessor.

Running on Windows

Works on GCC but not here.

Was unable to get any <> includes with -I to work, only defaults, and no subdirectories. We need to get mavgen compiling for the p2, so we're going to have to do at least a couple of layers of directory structures here, ideally without replacing all <> calls with "" and flattening the tree by hand.

[Wuerfel21]

The default include dir doesn't need to be on the command line at all, the compiler auto-finds it at a relative path to its executable.

Include paths like that do Work On My Machine^TM (Linux), though there seem to be some oddities when the path is in quotes, so maybe try unquoted ones.

[RbtsEvrwhr-Riley]

We've tested unquoted, absolute, relative, so far we have nothing working on the Windows boxes. I'll test it on Linux, I guess that's one way to make me put the big P2 projects into Jenkins early on

[RbtsEvrwhr-Riley]

Okay, so I've been testing this on Linux for a few days and did end up finding a couple of issues.

"/home/user/flexprop/bin/bin/flexspin" -2 -Dd -l --tabs=8 -D_BAUD=230400 -O1 --charset=utf8 -I "/home/user/flexprop/bin/include" -I "/home/user/PX4/PX4-Autopilot/src/modules/mavlink/mavlink" -I "/home/user/PX4/PX4_Autopilot/src/modules/mavlink" -I "/home/user/PX4/PX4-Autopilot/platforms/common/include" -I "/home/user/PX4/PX4-Autopilot/src/lib"  "/home/user/PX4/PX4-Autopilot/src/modules/mavlink/mavlink.c"

This is my current compiler setting, and:

#include <mavlink_bridge_header.h> does not find the file in "/home/user/PX4/PX4-Autopilot/src/modules/mavlink/mavlink_bridge_header.h" but it does find it if I just

#include "/home/user/PX4/PX4-Autopilot/src/modules/mavlink/mavlink_bridge_header.h"

Weirdly, #include <px4_platform_common/px4_config.h> WORKS, which is in "/home/user/PX4/PX4-Autopilot/platforms/common/include"

Similarly #include <checksum.h> in "/home/user/PX4/PX4-Autopilot/src/modules/mavlink/mavlink" works. But nothing in ""/home/user/PX4/PX4-Autopilot/src/modules/mavlink/" works unless it's manually specified.

Removing the nested -I for /mavlink/mavlink does NOT change any behaviors.

Right now this perceived inconsistency is appearing quite scary. I've tried isolating all of the -I flags, as well as isolating the include, and I cannot seem to get anything from that directory to include no matter what I test.

Here's a more isolated example.

"/home/user/flexprop/bin/bin/flexspin" -2 -Dd -l --tabs=8 -D_BAUD=230400 -O1    --charset=utf8 -I "/home/user/PX4/PX4_Autopilot/src/modules/mavlink" "/home/user/test.c"
Propeller Spin/PASM Compiler 'FlexSpin' (c) 2011-2025 Total Spectrum Software Inc. and contributors
Version 7.2.1-HEAD-v7.2.1 Compiled on: Apr 28 2025
test.c
error: Preprocessor errors:
/home/user/test.c:2: error: Can't open include file "mavlink/checksum.h"
    #include <mavlink/checksum.h>
/home/user/test.c:3: error: Can't open include file "mavlink.c"
    #include <mavlink.c>
2 errors in preprocessor.

child process exited abnormally
Finished at Wed Apr 30 14:07:14 2025

[totalspectrum]

Sorry that I've been slow to look at this, I haven't had much time lately. The flexcc preprocessor is a public domain one, mcpp, which is pretty mature and has passed a bunch of tests. So I'm surprised you're having trouble with it, although it's possible I've interfaced to it incorrectly in some respect. That said, everything I've tried has worked (and I just double checked with a few different combinations of paths and names).

Is there a typo on the command line? The command line above has -I "/home/user/PX4/PX4-Autopilot/src/lib" but you said the line #include "/home/user/PX4/PX4-Autopilot/src/modules/mavlink/mavlink_bridge_header.h" works... the former is looking in .../src/lib/... but the latter is in .../src/modules/... .

Another thing to check, particularly on Windows, is the case of file names. Windows generally doesn't care about the case, and flexspin/flexcc shouldn't, but there may be some instances where it does matter and they have to match exactly.

[totalspectrum]

Oh, and a general comment -- I see you're compiling a .cpp file. Flexspin has virtually no C++ support, it's really just a C compiler with a few (very few) useful extensions that happen to come from C++. If the code you're porting uses many C++ features, you'll probably have to use a real C++ compiler like LLVM or the riscvp2 GCC.

[totalspectrum]

Have you had a chance to double check your command line? It seems from the posted examples that this was a typo on the command line.