go build gopkg.in/gographics/imagick.v3/imagick: invalid flag in pkg-config --cflags: -fopenmp

[ghost]

CentOS7

sh$ uname -a

Linux VM_0_15_centos 3.10.0-693.5.2.el7.x86_64 #1 SMP Fri Oct 20 20:32:50 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux

Imagick.v3

rpm -Uvh ./init/ImageMagick-libs-7.0.7-22.x86_64.rpm
rpm -Uvh ./init/ImageMagick-7.0.7-22.x86_64.rpm
rpm -Uvh ./init/ImageMagick-devel-7.0.7-22.x86_64.rpm

sh$ pkg-config --cflags --libs MagickWand

-fopenmp -DMAGICKCORE_HDRI_ENABLE=1 -DMAGICKCORE_QUANTUM_DEPTH=16 -I/usr/include/ImageMagick-7 -lMagickWand-7.Q16HDRI -lMagickCore-7.Q16HDRI

sh$ go run somethingWithImagick.go

go build gopkg.in/gographics/imagick.v3/imagick: invalid flag in pkg-config --cflags: -fopenmp

sh$ go build somethingWithImagick.go

go build gopkg.in/gographics/imagick.v3/imagick: invalid flag in pkg-config --cflags: -fopenmp

imagick.v2

sh$ pkg-config --cflags --libs MagickWand

-fopenmp -I/usr/include/ImageMagick -lMagickWand -lMagickCor

sh$ go build main.go

go build gopkg.in/gographics/imagick.v2/imagick: invalid flag in pkg-config --cflags: -fopenmp

[justinfx]

Does it work when doing a normal build or install of your program? I have seen go run fail to work properly on cgo programs.

[ghost]

it works well when I build or run a program without importing imagick

[justinfx]

Thanks for answering that. I was getting at whether it would work when using go build with imagick, and you covered it. I think you are hitting this: golang/go#23739
Are you using go-1.9.4? They introduced security updates in cgo which prevent various flags from being used.

It was reported already to be added to the whitelist:
golang/go#23749

The workaround for now is to manually whitelist them by setting CGO_CFLAGS_ALLOW or CGO_LDFLAGS_ALLOW

[ghost]

sh$ go version

go version go1.9.4 linux/amd64

sh$ go env

GOARCH="amd64"
GOBIN=""
GOEXE=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOOS="linux"
GOPATH="/go"
GORACE=""
GOROOT="/bin/go"
GOTOOLDIR="/usr/local/go/pkg/tool/linux_amd64"
GCCGO="gccgo"
CC="gcc"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build718350618=/tmp/go-build -gno-record-gcc-switches"
CXX="g++"
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"

[ghost]

sh$ echo ${CGO_LDFLAGS_ALLOW}

.*.a$

sh$ go run main.go

go build gopkg.in/gographics/imagick.v2/imagick: invalid flag in pkg-config --cflags: -fopenmp

sh$ go run -tags no_pkgconfig main.go

gopkg.in/gographics/imagick.v2/imagick

../../gopkg.in/gographics/imagick.v2/imagick/affine_matrix.go:8:29: fatal error: wand/MagickWand.h: No such file or directory
#include <wand/MagickWand.h>
^
compilation terminated.

[justinfx]

This is the workaround, from what the ticket says:

export CGO_CFLAGS_ALLOW='-fopenmp'

The failing flag is a compile flag, so you need to manually whitelist it.

go run -tags no_pkgconfig main.go

You can't do this without telling it explicit CGO_CFLAGS and CGO_LDFLAGS. That turns off pkg-config which means its now not finding ImageMagick

[justinfx]

Closing this since the problem relates to the cgo whitelist in the latest Go release.