cmd/go: problems with cgo_resnew when cross-compiling on freebsd for linux

[ov]

Go version

go version go1.22.1 freebsd/amd64

Output of go env in your module/workspace:

GO111MODULE=''
GOARCH='amd64'
GOBIN=''
GOCACHE='/home/ov/.cache/go-build'
GOENV='/home/ov/.config/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFLAGS=''
GOHOSTARCH='amd64'
GOHOSTOS='freebsd'
GOINSECURE=''
GOMODCACHE='/home/ov/go/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='freebsd'
GOPATH='/home/ov/go'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/usr/local/go122'
GOSUMDB='sum.golang.org'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/usr/local/go122/pkg/tool/freebsd_amd64'
GOVCS=''
GOVERSION='go1.22.1'
GCCGO='gccgo'
GOAMD64='v1'
AR='ar'
CC='cc'
CXX='clang++'
CGO_ENABLED='1'
GOMOD='/home/ov/...../go.mod'
GOWORK=''
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
PKG_CONFIG='pkg-config'
GOGCCFLAGS='-fPIC -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build2801792256=/tmp/go-build -gno-record-gcc-switches'

What did you do?

I'm trying to cross-compile a project for Linux on a FreeBSD host:

GOOS=linux GOARCH=amd64 CGO_ENABLED=1 CC="gcc13" CXX="g++13" go build -ldflags "-extldflags -static" -o app

I tried different CC/CXX options (clang, gcc, amd64-gcc) - they all behave the same.

What did you see happen?

Here's what I get:

GOOS=linux GOARCH=amd64 CGO_ENABLED=1 CC="gcc13" CXX="g++13" go build -ldflags "-extldflags -static" -o app
# net
/usr/local/go122/src/net/cgo_resnew.go:20:76: cannot use _Ctype_socklen_t(len(b)) (value of type _Ctype_uint) as _Ctype_ulong value in argument to (_C2func_getnameinfo)

There was a similar discussion about this in #33101 and the solution was to set CGO_ENABLED=0. The problem is that my project has some c++ code that needs to be built, so I can't disable cgo.

If I manually modify the flags in cgo_resnew.go and cgo_resold.go so the latter is used for Linux, the compiling progresses, but it then fails on linking with:

/usr/local/go122/pkg/tool/freebsd_amd64/link: running g++13 failed: exit status 1
/usr/local/bin/ld: cannot find -lresolv: No such file or directory
collect2: error: ld returned 1 exit status

I am not sure if modifying the resnew/old was the right thing, so decided to not dig any deeper and create the report instead.

What did you expect to see?

I expect to be able to do cross-compile builds that use the net module with CGO_ENABLED=1. I can do this on Mac with musl, I can do normal builds on FreeBSD. I expect the cross-builds work on FreeBSD, as well.

Thank you.

[seankhliao]

Cross compilation C toolchains typically have the target name as part of their executable names. I don't see that here, so it looks like you're trying to use the host toolchain.

Unlike many projects, the Go project does not use GitHub Issues for general discussion or asking questions. GitHub Issues are used for tracking bugs and proposals only.

For questions please refer to https://github.com/golang/go/wiki/Questions

[Manamama]

This worked in Termux, and in Debian prooted under Termux: export CGO_ENABLED=0 to compile pdfcpu.

Re: cannot find -lresolv - this very ugly hack, running in a separate session, fixes it, but too often the compilation then fails at the very last step: "all ok, the operation successful, but the patient died", that is no error but no .so file produced, either. For the record:

while true; do
    date && sed -i '/-lresolv/d' $(grep -rl 'lresolv' .) 
date && sed -i '/-lresolv/d' $(grep -rl 'lresolv' $TMPDIR)
    sleep 0.1  # Optional: Adjust the sleep duration as needed
done

[Manamama]

Re: #66839 (comment) - for the record: I do not remember which module caused that -lresov (resolve library) installation error in Termux (aarch64) by now - but almost sure that it was one of the modules required by Docling https://github.com/DS4SD/docling, probably this: docling-parse.

Ref:

pip show docling
Name: docling
Version: 2.14.0
Summary: SDK and CLI for parsing PDF, DOCX, HTML, and more, to a unified document representation for powering downstream workflows such as gen AI applications.
Home-page: https://github.com/DS4SD/docling
Author: Christoph Auer
Author-email: cau@zurich.ibm.com
License: MIT
Location: /home/zezen/.local/lib/python3.10/site-packages
Requires: beautifulsoup4, certifi, deepsearch-glm, docling-core, docling-ibm-models, docling-parse, easyocr, filetype, huggingface_hub, lxml, marko, openpyxl, pandas, pydantic, pydantic-settings, pypdfium2, python-docx, python-pptx, requests, rtree, scipy, typer