golang/go

cmd/cgo: cgo + static const int results in "undefined reference" on linux

Open

#40,820 opened on Aug 16, 2020

View on GitHub
 (6 comments) (1 reaction) (0 assignees)Go (19,008 forks)batch import
NeedsInvestigationcompiler/runtimehelp wanted

Repository metrics

Stars
 (133,883 stars)
PR merge metrics
 (No merged PRs in 30d)

Description

What version of Go are you using (go version)?

Does this issue reproduce with the latest release?

Have not tried

What operating system and processor architecture are you using (go env)?

What did you do?

Linking of a program referring to static const int fails with undefined reference:

foo.h

static const int BAR = 1;

foo.go

package main

/*
#include "foo.h"
*/
import "C"
import "fmt"

const (
  BAR = int(C.BAR)
)

func main() {
  fmt.Println(BAR)
}

What did you expect to see?

Compilation succeeds on linux as it does on darwin

What did you see instead?

go build
/usr/bin/ld: $WORK/b001/_cgo_main.o:/tmp/go-build/cgo-generated-wrappers:2: undefined reference to `BAR'
collect2: error: ld returned 1 exit status

Contributor guide

Research direction
Investigate the cgo code generation for 'static const int' on Linux vs Darwin. Look at how cgo handles static constants and the linker error. Check recent commits or related issues about cgo symbol handling.
Tech stack
go
Domain
backend
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
GocgoC compiler
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
50