Problems Cross Compiling [Mac + BSD] about serial

[dantheman213]

Hi, I have enjoyed using your serial library so far. But unfortunately I'm having this exact same issue on my own project. It's most unfortunate I can't easily create a pipeline to compile for all platforms using a single make command.

dan@DAN-DESKTOP:/mnt/c/Users/danie/repos/gps-atlas$ make build-macos
export GOOS=darwin && \
export GOARCH=amd64 && \
export GPSATLAS_BIN_PATH=bin/macos/gps-atlas && \
make build
make[1]: Entering directory '/mnt/c/Users/danie/repos/gps-atlas'
CGO_ENABLED=0 \
GO111MODULE=on \
go build \
-installsuffix "static" \
-ldflags="-X 'main.Version=$(cat version)'" \
-o bin/macos/gps-atlas \
$(find cmd/app/*.go)
# github.com/tarm/serial
/home/dan/go/pkg/mod/github.com/tarm/[email protected]/serial.go:128:28: undefined: Port
/home/dan/go/pkg/mod/github.com/tarm/[email protected]/serial.go:139:9: undefined: openPort
Makefile:8: recipe for target 'build' failed
make[1]: *** [build] Error 2
make[1]: Leaving directory '/mnt/c/Users/danie/repos/gps-atlas'
Makefile:29: recipe for target 'build-macos' failed
make: *** [build-macos] Error 2
dan@DAN-DESKTOP:/mnt/c/Users/danie/repos/gps-atlas$

[tarm]

Hi @tsteinholz

This package does aim to be cross platform, but cross-compiling (with gox or manually) is tricky right now. I think native compilation should work on all of the *bsd platforms. For windows in particular, both native and cross compiling should work like this:

$ GOOS=windows go install github.com/tarm/serial
$ ls -l $GOPATH/pkg/windows_amd64/github.com/tarm
total 72
-rw-r--r--. 1 tarm tarm 72410 Jan 30 20:22 serial.a

Specifically the issue with cross-compiling for posix platforms is that tarm/serial uses cgo+termios.h to keep things portable. The termios.h interface abstracts some of the syscall and ioctl differences in serial handling between different platforms. Take a look at the "build constraints" and cgo code here:
https://github.com/tarm/serial/blob/master/serial_posix.go#L1-L9

You might be able to make it work by passing the -cgo option to gox, but cross-compiling cgo code may be tricky and I have not tried it myself.

I would be interested/open to syscall+ioctl based solutions. Those would likely allow cross compiling more easily, but also would be much more closely tied to each architecture/platform.

Patches welcome!