cgo: generate invalid header files

[KnisterPeter]

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

$ go version
go version go1.20.4 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=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/xxx/.cache/go-build"
GOENV="/home/xxx/.config/go/env"
GOEXE=""
GOEXPERIMENT=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOINSECURE=""
GOMODCACHE="/home/xxx/go/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/home/xxx/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/home/xxx/sdk/go1.20.4"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/home/xxx/sdk/go1.20.4/pkg/tool/linux_amd64"
GOVCS=""
GOVERSION="go1.20.4"
GCCGO="gccgo"
GOAMD64="v1"
AR="ar"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD="/home/xxx/source/xxx/go.mod"
GOWORK=""
CGO_CFLAGS="-O2 -g"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-O2 -g"
CGO_FFLAGS="-O2 -g"
CGO_LDFLAGS="-O2 -g"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build1261571602=/tmp/go-build -gno-record-gcc-switches"

What did you do?

package main

/*
#include <security/pam_modules.h>
*/
import "C"

//export pam_sm_authenticate
func pam_sm_authenticate(pamh *C.pam_handle_t, flags C.int, argc C.int, argv **C.char) C.int {
    return C.PAM_USER_UNKNOWN
}

Compiling this with go build -buildmode=c-shared -o pam_module.so

What did you expect to see?

This is expected to compile to a shared library

What did you see instead?

It fails with the following compiler error:

# github.com/xxx/pam_module
In file included from _cgo_export.c:4:
cgo-gcc-export-header-prolog:43:12: error: conflicting types for ‘pam_sm_authenticate’
In file included from c.go:4,
                 from _cgo_export.c:4:
/usr/include/security/pam_modules.h:34:5: note: previous declaration of ‘pam_sm_authenticate’ was here
   34 | int pam_sm_authenticate(pam_handle_t *pamh, int flags,
      |     ^~~~~~~~~~~~~~~~~~~
_cgo_export.c:24:5: error: conflicting types for ‘pam_sm_authenticate’
   24 | int pam_sm_authenticate(pam_handle_t* pamh, int flags, int argc, char** argv)
      |     ^~~~~~~~~~~~~~~~~~~
In file included from c.go:4,
                 from _cgo_export.c:4:
/usr/include/security/pam_modules.h:34:5: note: previous declaration of ‘pam_sm_authenticate’ was here
   34 | int pam_sm_authenticate(pam_handle_t *pamh, int flags,
      |     ^~~~~~~~~~~~~~~~~~~
make: *** [Makefile:3: build] Error 2

[seankhliao]

sorry, not a supported thing see ex https://stackoverflow.com/questions/32938558/cgo-cant-find-way-to-use-callbacks-with-const-char-argument https://stackoverflow.com/questions/63207929/unable-to-export-go-function-with-const-c-char-parameter

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