go: runtime/cgo: macro expansion producing 'defined' has undefined behavior
What version of Go are you using (go version
)?
$ go version go version go1.14.2 darwin/amd64
Does this issue reproduce with the latest release?
Yes
What operating system and processor architecture are you using (go env
)?
OS: macOS Catalina 10.15.4
go env
Output
$ go envGO111MODULE=“” GOARCH=“amd64” GOBIN=“” GOCACHE=“/Users/sr/Library/Caches/go-build” GOENV=“/Users/sr/Library/Application Support/go/env” GOEXE=“” GOFLAGS=“” GOHOSTARCH=“amd64” GOHOSTOS=“darwin” GOINSECURE=“” GONOPROXY=“” GONOSUMDB=“” GOOS=“darwin” GOPATH=“/Users/sr/go” GOPRIVATE=“” GOPROXY=“https://proxy.golang.org,direct” GOROOT=“/usr/local/go” GOSUMDB=“sum.golang.org” GOTMPDIR=“” GOTOOLDIR=“/usr/local/go/pkg/tool/darwin_amd64” GCCGO=“gccgo” AR=“ar” 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=/var/folders/7t/mh0c8z9x6rn72vfl7jxrqh4r0000gn/T/go-build284435102=/tmp/go-build -gno-record-gcc-switches -fno-common”
What did you do?
Try to run this code:
package main
import (
"fmt"
"log"
"net/http"
)
func main() {
http.HandleFunc("/", indexHandler)
log.Fatal(http.ListenAndServe(":9999", nil))
}
// handler echoes r.URL.Path
func indexHandler(w http.ResponseWriter, req *http.Request) {
fmt.Fprintf(w, "URL.Path = %q\n", req.URL.Path)
}
What did you expect to see?
Expect the program to run.
What did you see instead?
# runtime/cgo
In file included from gcc_darwin_amd64.c:6:
/usr/local/include/pthread.h:331:6: error: macro expansion producing 'defined' has undefined behavior [-Werror,-Wexpansion-to-defined]
/usr/local/include/pthread.h:200:2: note: expanded from macro '_PTHREAD_SWIFT_IMPORTER_NULLABILITY_COMPAT'
/usr/local/include/pthread.h:331:6: error: macro expansion producing 'defined' has undefined behavior [-Werror,-Wexpansion-to-defined]
/usr/local/include/pthread.h:200:34: note: expanded from macro '_PTHREAD_SWIFT_IMPORTER_NULLABILITY_COMPAT'
/usr/local/include/pthread.h:332:5: error: declaration of built-in function 'pthread_create' requires inclusion of the header <pthread.h> [-Werror,-Wbuiltin-requires-header]
/usr/local/include/pthread.h:540:6: error: macro expansion producing 'defined' has undefined behavior [-Werror,-Wexpansion-to-defined]
/usr/local/include/pthread.h:200:2: note: expanded from macro '_PTHREAD_SWIFT_IMPORTER_NULLABILITY_COMPAT'
/usr/local/include/pthread.h:540:6: error: macro expansion producing 'defined' has undefined behavior [-Werror,-Wexpansion-to-defined]
/usr/local/include/pthread.h:200:34: note: expanded from macro ####'_PTHREAD_SWIFT_IMPORTER_NULLABILITY_COMPAT'
About this issue
- Original URL
- State: closed
- Created 4 years ago
- Comments: 23 (4 by maintainers)
This works for me except
-Wbuiltin-requires-header
->-Wno-builtin-requires-header
. Then, what add to env is:CGO_CPPFLAGS=-Wno-error -Wno-nullability-completeness -Wno-expansion-to-defined -Wno-builtin-requires-header
@kangkang59812
export CGO_CPPFLAGS="-Wno-error -Wno-nullability-completeness -Wno-expansion-to-defined -Wno-builtin-requires-header"
Then check your environment via
go env
.Thank you all for your help. I finally found out that my Xcode command line tools can not work as expectation. What I did is to run these lines in Terminal.
Hi! I already encountered an error like that one. I’ve had to add
CGO_CPPFLAGS=-Wno-error -Wno-nullability-completeness -Wno-expansion-to-defined -Wbuiltin-requires-header
to my env to make it work. I think that it’s just removing the compilation flags.My program is the same than yours and I was able to make it work using this. I’m using MacOs Catalina 10.15.4
I met the same issue when using gvm to install go1.16 in Big Sur. Your solution totally works!
where to add and how?
found out… I recently symlinked gcc headers into usr/local/include to get some other project running. After removing these symlinks from usr/local/include, everything works fine again