The +build constraints on cgo_resnew.go do not appear to allow freebsd: it should be using cgo_resold.go instead.

Can you reproduce this failure using a sequence of go commands rather than the ci/build.sh wrapper?

Ah, yeah: ci/build.sh is explicitly cross-compiling, so presumably you don't have the correct C headers for the target platforms.

Cross-compiles don't enable cgo by default, for that exact reason. Do you have CGO_ENABLED explicitly set in your environment? If so, what happens if you unset it?

Same errors in build log https://storage.googleapis.com/go-build-log/9e20f242/freebsd-amd64-12_0_3ca8deda.log

@cuonglm, was that a flake, or did you find a workaround?

@bcmills it does not seem to be a flake, it occrurred when I cross-compile with cgo enable on freebsd.

In my CL, I change the test to run on Linux only.

Have the same problem here building one of our packages, confirmed on:
go version go1.12.9 freebsd/amd64

Setting CGO_ENABLED=0 fixed it but I thought cross-compile did this by default?

@stevenh, @cuonglm, if you can reproduce this reliably please post exact instructions, including the output of go env and uname -sv.

I can reproduce the observed symptom on FreeBSD 12.1 by running:

CGO_ENABLED=1 GOOS=linux GOARCH=amd64 go build net

Without the explicit CGO_ENABLED=1, that command succeeds.

I note that sshcode/build.sh explicitly sets GOOS=linux, so all that would be required to reproduce it there is CGO_ENABLED=1.

So my question to all of you is: have you seen this issue with CGO_ENABLED unset in the environment of the go command in which you observed the failure?

With 1.12.9 I get

go build
# net
/usr/local/go/src/net/cgo_resnew.go:21:87: cannot use _Ctype_uint(len(b)) (type _Ctype_uint) as type _Ctype_ulong in argument to _C2func_getnameinfo

go env
GOARCH="amd64"
GOBIN="/data/go/bin"
GOCACHE="/root/.cache/go-build"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="freebsd"
GOOS="linux"
GOPATH="/data/go"
GOPROXY=""
GORACE=""
GOROOT="/usr/local/go"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/freebsd_amd64"
GCCGO="gccgo"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
GOMOD=""
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build371148949=/tmp/go-build -gno-record-gcc-switches"

uname -sv
FreeBSD FreeBSD 12.0-RELEASE-p10 MULTIPLAY-r5

env |grep GO
GOPATH=/data/go
GOHOME=/data/go
GOBIN=/data/go/bin
GOOS=linux

With 1.13 it doesn't exhibit the same behaviour, and notably go env has changed to CGO_ENABLED="0" which under 1.12.9 was CGO_ENABLED="1" even though its not set in my environment.

go env
GO111MODULE=""
GOARCH="amd64"
GOBIN="/data/go/bin"
GOCACHE="/root/.cache/go-build"
GOENV="/root/.config/go/env"
GOEXE=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="freebsd"
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/data/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/local/go"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/freebsd_amd64"
GCCGO="gccgo"
AR="ar"
CC="clang"
CXX="clang++"
CGO_ENABLED="0"
GOMOD=""
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build722621377=/tmp/go-build -gno-record-gcc-switches"

In addition removing GOOS=linux from my env makes 1.13 automatically set CGO_ENABLED="1" so it looks like 1.12 had an issue correctly configuring CGO_ENABLED when cross compiling.

So to confirm looks like this is fixed in 1.13.

Thanks for the followup.

#33673 seems closely related. The report there suggests that the default value of CGO_ENABLED for cross-compiled builds may have changed back to 0 (as intended) in CL 171137.

So I'm going to call this “fixed in 1.13”, but please open a new issue if it crops up again!