-Wmacro-redefined warning with SW_MAX and Linux 6.16 headers

[correctmost]

• Device name: N/A

• Device model identifier: N/A

• libwacom version: 3c2df35 compiled on Arch Linux

• I understand that libwacom does not affect whether the device works (see Troubleshooting)

Bug description

I see the following warning when compiling with Linux 6.16 headers:

[11/20] Compiling C object libwacom.so.9.0.0.p/libwacom_libwacom-database.c.o
In file included from ../libwacom/libwacom-database.c:34:
../include/linux/input-event-codes.h:927:9: warning: 'SW_MAX' macro redefined [-Wmacro-redefined]
  927 | #define SW_MAX                  0x10
      |         ^
/usr/include/linux/input-event-codes.h:929:9: note: previous definition is here
  929 | #define SW_MAX                  0x11
      |         ^
1 warning generated.

Related commit: torvalds/linux@67890d5

Version info

• 3c2df35 compiled on Arch Linux
• linux 6.15.9.arch1-1
• linux-api-headers 6.16-1

[whot]

Can you attach the full build output (as a txt file) please? We shouldn't be using the system headers so some flag is being ignored here.

[correctmost]

Sure, I have attached meson-logs/meson-log.txt and a text file with the output from meson compile.

meson-log.txt
meson-compile-output.txt

[correctmost]

I applied the patch from #900 and still see the warning:

In file included from ../libwacom/libwacom-database.c:42:
../include/linux/input-event-codes.h:927:9: warning: 'SW_MAX' macro redefined [-Wmacro-redefined]
  927 | #define SW_MAX                  0x10
      |         ^
/usr/include/linux/input-event-codes.h:929:9: note: previous definition is here
  929 | #define SW_MAX                  0x11
      |         ^
1 warning generated.

---

Here's the verbose clang invocation:

[10/20] clang -Ilibwacom.so.9.0.0.p -I. -I.. -I../include -I../libwacom -I/usr/include/gudev-1.0 -I/usr/include/glib-2.0 -I/usr/lib/glib-2.0/include -I/usr/include/sysprof-6 -I/usr/include/libevdev-1.0 -fvisibility=hidden -fdiagnostics-color=always -D_FILE_OFFSET_BITS=64 -Wall -Winvalid-pch -Wextra -std=gnu99 -Wno-unused-parameter -Wmissing-prototypes -Wstrict-prototypes -Wundef -Wpointer-arith -Wuninitialized -Winit-self -Wstrict-prototypes -Wimplicit-fallthrough -Wredundant-decls -Wincompatible-pointer-types -Wformat=2 -Wsign-compare -Wmissing-declarations -fPIC -pthread '-DG_LOG_DOMAIN="libwacom"' '-DDATADIR="/usr/local/share/libwacom"' '-DETCDIR="/usr/local/etc/libwacom"' -MD -MQ libwacom.so.9.0.0.p/libwacom_libwacom-database.c.o -MF libwacom.so.9.0.0.p/libwacom_libwacom-database.c.o.d -o libwacom.so.9.0.0.p/libwacom_libwacom-database.c.o -c ../libwacom/libwacom-database.c

---

It seems like linux/input-event-codes.h is being included through this path:

• libevdev-1.0/libevdev/libevdev.h -> linux/input.h -> linux/input-event-codes.h

[whot]

I've pushed another patch to #900 to fix the include guards, this should do the trick now because the system header will prevent our header to get included (which is fine in this case, though long-term we should fix this).

[correctmost]

Thanks, the updated patch fixes the warning with gcc and clang.