crypto/x509: cgo errors on for loop initial declarations with gcc pre-C99

[avinashrd]

Please answer these questions before submitting your issue. Thanks!

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

1.10

Does this issue reproduce with the latest release?

Yes

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

GOARCH="amd64"
GOBIN="/Users/avinashrd/Downloads/projects/golang/bin"
GOCACHE="/Users/avinashrd/Library/Caches/go-build"
GOEXE=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GOOS="darwin"
GOPATH="/Users/avinashrd/Downloads/projects/golang"
GORACE=""
GOROOT="/usr/local/opt/go/libexec"
GOTMPDIR=""
GOTOOLDIR="/usr/local/opt/go/libexec/pkg/tool/darwin_amd64"
GCCGO="gccgo"
CC="/usr/local/Cellar/gcc49/4.9.1/bin/gcc-4.9"
CXX="/usr/local/Cellar/gcc49/4.9.1/bin/g++-4.9"
CGO_ENABLED="1"
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=/var/folders/w8/y97pxwvj35xcsw9vmh2s3gzr0000gn/T/go-build181075919=/tmp/go-build -gno-record-gcc-switches -fno-common"

What did you do?

try to run the application in Jetbrains GoLand editor

If possible, provide a recipe for reproducing the error.
A complete runnable program is good.
A link on play.golang.org is best.

What did you expect to see?

expected to see the valid output

What did you see instead?

/usr/local/opt/go/libexec/src/crypto/x509/root_cgo_darwin.go:104:2: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
for (int i = 0; i < numDomains; i++) {
^
/usr/local/opt/go/libexec/src/crypto/x509/root_cgo_darwin.go:104:2: note: use option -std=c99, -std=gnu99, -std=c11 or -std=gnu11 to compile your code
/usr/local/opt/go/libexec/src/crypto/x509/root_cgo_darwin.go:112:3: error: 'for' loop initial declarations are only allowed in C99 or C11 mode
for (int j = 0; j < numCerts; j++) {

[ianlancetaylor]

Thanks. This is happening because you are running quite an old version of GCC. I'll send a fix.

[gopherbot]

Change https://golang.org/cl/101215 mentions this issue: crypto/x509: don't require C99 mode in Darwin cgo code

[avinashrd]

@ianlancetaylor

Thanks for the reply.
If I update my GCC using brew, will that fix the issue?

I didn't understand the comment by @gopherbot .

[FiloSottile]

@avinashrd Yes, if you install a more recent version of GCC (for example brew install gcc which will currently install 7.3) and set it as your CC/CXX environment variables, it should fix your issue.

@gopherbot was just reporting that we are working on a fix in Go, but that will not be available until Go 1.11, and it might not be enough to make GCC 4.9 work anyway.

[avinashrd]

I updated to 7.3 as suggested and ran the same program. I am getting this error now

crypto/x509

In file included from /System/Library/Frameworks/Security.framework/Headers/AuthSession.h:32:0,
from /System/Library/Frameworks/Security.framework/Headers/Security.h:43,
from /usr/local/Cellar/go/1.10/libexec/src/crypto/x509/root_cgo_darwin.go:17:
/System/Library/Frameworks/Security.framework/Headers/Authorization.h:193:7: error: variably modified 'bytes' at file scope
char bytes[kAuthorizationExternalFormLength];
^~~~~

Go Env :

GOARCH="amd64"
GOBIN="/Users/xxx/Downloads/projects/golang/bin"
GOCACHE="/Users/xxx/Library/Caches/go-build"
GOEXE=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GOOS="darwin"
GOPATH="/Users/xxxx/Downloads/projects/golang"
GORACE=""
GOROOT="/usr/local/opt/go/libexec"
GOTMPDIR=""
GOTOOLDIR="/usr/local/opt/go/libexec/pkg/tool/darwin_amd64"
GCCGO="gccgo"
CC="/usr/local/Cellar/gcc/7.3.0_1/bin/gcc-7"
CXX="/usr/local/Cellar/gcc/7.3.0_1/bin/g++-7"
CGO_ENABLED="1"
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=/var/folders/w8/y97pxwvj35xcsw9vmh2s3gzr0000gn/T/go-build575805343=/tmp/go-build -gno-record-gcc-switches -fno-common"