STMCubeIDE + LwIP : lwip/opt.h no such file

[Joerg Wagner]

I built a tiny project from scratch with LwIP (without FreeRTOS).

CubeMX generates a project without any errors which I can compile and run.

But when I modify my source code in main.c every compile stops with:

../Inc/lwip.h:28:10: fatal error: lwip/opt.h: No such file or directory

In Tool Settings->MCU GCC Compiler->Includes are no entries in the list.

I added at least:

../Middlewares/Third_Party/LwIP/src/include

../Middlewares/Third_Party/LwIP/system

../Middlewares/Third_Party/LwIP/src/include/lwip

../Middlewares/Third_Party/LwIP/src/include/lwip/apps

../Middlewares/Third_Party/LwIP/src/include/lwip/priv

../Middlewares/Third_Party/LwIP/src/include/lwip/prot

Same problem.

But when I make a change in CubeMX, save it and new code is generated

the project can be compiled.

How can I fix this to be able to compile a project with LwIP in STMCubeIDE ?

Thank you.

[Markus GIRDLAND]

I tried creating a LwIP project but I can't reproduce your issue. I can make changes to my main.c file just fine and it still works.

If you can specify a way for me to reproduce this, step-by-step then I might be able to be more helpful.

[Joerg Wagner]

I created now a second project and copied all the include paths into the first one.

Now it works, I can compile after changing the code.

Like I said, the include paths list was empty.

Thank you.

[Joerg Wagner]

After this fix I changed my code concerning SPI only.

But sometimes this occurs:

.../Debug/../Src/ethernetif.c:563: undefined reference to `etharp_output'

Src/lwip.o: In function `MX_LWIP_Init':

.../Debug/../Src/lwip.c:72: undefined reference to `lwip_init'

.../Debug/../Src/lwip.c:80: undefined reference to `netif_add'

.../Debug/../Src/lwip.c:83: undefined reference to `netif_set_default'

.../Debug/../Src/lwip.c:88: undefined reference to `netif_set_up'

.../Debug/../Src/lwip.c:93: undefined reference to `netif_set_down'

.../Debug/../Src/lwip.c:99: undefined reference to `ethernet_input'

collect2: error: ld returned 1 exit status

make: *** [makefile:41: pccv4_767.elf] Error 1

( The ... represents the full correct path)

I do not use network functions this time (comes later), LwIP is just enabled in the project.

The only way I know to get rid of this errors is to change the .ioc file with CubeMX and regenerate the project.

This can not be the way to work serious.

[Markus GIRDLAND]

So this error appears and you can "work around" that problem by regenerating the project?

And when you do so everything works fine again?

[Joerg Wagner]

Yes. Regenerating is the magic.

But lwip compiling errors do not occur after each compile.

It happens sometimes.

Edited: It happens most of the time when I start STM32CubeIDE.

I came from SW4STM32 and never had a similar problem.