x/tools/gopls: could not import C (no package for import C) when importing static libraries

[Zincr0]

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

$ go version
go version go1.14.6 linux/amd64

Does this issue reproduce with the latest release?

yes

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

go env Output

$ go env
GO111MODULE="auto"

GOARCH="amd64"

GOBIN=""

GOCACHE="/home/vscode/.cache/go-build"

GOENV="/home/vscode/.config/go/env"

GOEXE=""

GOFLAGS=""

GOHOSTARCH="amd64"

GOHOSTOS="linux"

GOINSECURE=""

GONOPROXY=""

GONOSUMDB=""

GOOS="linux"

GOPATH="/go"

GOPRIVATE=""

GOPROXY="https://proxy.golang.org,direct"

GOROOT="/usr/local/go"

GOSUMDB="sum.golang.org"

GOTMPDIR=""

GOTOOLDIR="/usr/local/go/pkg/tool/linux_amd64"

GCCGO="gccgo"

AR="ar"

CC="gcc"

CXX="g++"

CGO_ENABLED="1"

GOMOD="/goapp/app/go.mod"

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 -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build968699808=/tmp/go-build -gno-record-gcc-switches"

What did you do?

I'm here from #35721 since it seems this particular case is not the same issue. Trying to import a static library using "import C" gives a "could not import C (no package for import C)" in vscode, the code however, can compile and run with no problems with go build.

sample go code:

package main

// #cgo CFLAGS: -g -Wall -I/usr/src/myapp
// #cgo LDFLAGS: /usr/src/myapp/libdoecho.a
// #include "libdoecho.h"
import "C"
import "unsafe"
import "fmt"

func test1() {
    aCstring := C.CString("Hello")
    res := C.doecho(aCstring)
    aGOstring := C.GoString(res)
    C.free(unsafe.Pointer(aCstring))
    C.freeThePointer(res)
    fmt.Println("%v", aGOstring)
}

sample .h code:

#ifndef libdoecho
#define libdoecho

#include <stdarg.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdlib.h>

char *doecho(const char *s);

void freeThePointer(char *s);

#endif /* libdoecho */

libdoecho.a is a library wich exposes the "doecho" and "freeThePointer" functions. A string enters and a string is returned.

What did you expect to see?

import C should not give the "could not import C (no package for import C)" error on vscode, since the code does compile and run without problems with go build.

What did you see instead?

A "could not import C (no package for import C)" error.

[ianlancetaylor]

What command did you run to produce that error?

[Zincr0]

I'm just opening the code on vscode

[heschi]

Please follow https://github.com/golang/tools/blob/master/gopls/doc/troubleshooting.md and attach a log.

[Zincr0]

I was preparing my system to get some logs when i copied the code to a new file and... there was no error, the same code on 2 files just with different test function name, the old one showing "could not import C" while the new one does not, so i deleted the old one and renamed the new one and bum! no more errors and the code now runs fine on vscode. Can this be a cache issue?, i updated recently to gopls 0.4.4. Sadly i can't get the logs now, but this issue may be useful to somebody else...

[ianlancetaylor]

Thanks. Closing the issue since it is working now.