direwolf dev branch will not build with gpsd 3.20

[n7nix]

Using this version of direwolf on 1/06/2020
wget https://github.com/wb2osz/direwolf/archive/dev.zip
Direwolf will not build with: gpsd -V
gpsd: 3.20 (revision 3.20)

[ 29%] Building C object src/CMakeFiles/gen_packets.dir/gen_packets.c.o
/usr/local/src/direwolf-dev/src/dwgpsd.c:65:2: error: #error libgps API version might be incompatible.
#error libgps API version might be incompatible.

[ 36%] Building C object src/CMakeFiles/atest.dir/dwgpsd.c.o
/usr/local/src/direwolf-dev/src/dwgpsd.c:65:2: error: #error libgps API version might be incompatible.
#error libgps API version might be incompatible.

[n7nix]

$ grep -i gpsd_api /usr/local/include/gps.h
#define GPSD_API_MAJOR_VERSION 9 /* bump on incompatible changes /
#define GPSD_API_MINOR_VERSION 0 / bump on compatible changes */
grep -A 3-i gpsd_api dwgpsd.c
grep: 3-i: invalid context length argument
pi@raspberrypi:/usr/local/src/direwolf-dev/src $ grep -A 3 -i gpsd_api dwgpsd.c
// Also compatible with API 7 & 8 with conditional compilation later.

#if GPSD_API_MAJOR_VERSION < 5 || GPSD_API_MAJOR_VERSION > 8
#error libgps API version might be incompatible.
#endif

[wb2osz]

Until I get a chance to evaluate this properly, ...

What happens if you simply remove the "#error ..." line? Maybe the API changes are only for functions not used here.

[n7nix]

I changed the upper API_MAJOR_VERSION number in this line in dwgpsd.c
#if GPSD_API_MAJOR_VERSION < 5 || GPSD_API_MAJOR_VERSION > 9
and direwolf builds fine.
I don't use any direwolf gps functionality so I'm not a good test subject but I'm happy with the build.

[mpannen1979]

I just built a version of direwolf from dev, and I get the same error as n7nix. I bypassed the version check for GPSD in dwgpsd.c file.

However, when I run direwolf, it just repeats message 'Waiting for GPSD...' over and over.

cgps and gpsd DO work by themselves in this case. The GPS is working and locking, etc.

[mpannen1979]

I am using archlinuxarm.

I worked around this by installing previous version of gpsd from scratch.

I had to go back to version 3.18 from gpsd website. Versions 3.19 and 3.20 did not work properly for me.

[mdomsch]

Fedora rawhide (will be 32) includes gpsd 3.20 with it's API version 9, so at present this fails there. If there's a direwolf 1.6 release imminent, I'd love to include that in Fedora as well.

[mdomsch]

Fedora 32 reverted gpsd to v3.19 to avoid the APIv9 changes this late in the release cycle. That buys another 3-4 months before this has to be addressed for Fedora's timetables.

[wb2osz]

Caught up with API version 9 and 10 changes.
Tested with most recent version here: https://gitlab.com/gpsd/gpsd.git

commit 74cf91c in dev branch.

Leaving this open for a while in case there is any additional feedback.

[DakotaNelson]

Thanks for the patch, wb2osz! Has there been any movement toward getting it merged into main?

[wb2osz]

Caught up with the API changes in the latest libgps source code. This is in both dev branches and the 1.6 release.