使用 Go 1.5 buildmode=c-archive 和 net/http。从 C 链接的服务器

Question

即将发布的 Go 1.5 附带 new buildmodes which allow for exporting Go symbols to be linked and called from C code. I've been playing around with it and got basic "Hello world" examples working, but now I'm trying to link a Go library which starts a net/http.Server and it's failing. The code looks like this (it's also available here):

gohttplib.go:

package main

import "C"
import "net/http"

//export ListenAndServe
func ListenAndServe(caddr *C.char) {
    addr := C.GoString(caddr)
    http.ListenAndServe(addr, nil)
}

func main() {}

examples/c/main.c:

#include <stdio.h>
#include "../../gohttplib.h"

int main()
{
    ListenAndServe(":8000");
    return 0;
}

生成 statically-linked object 和 headers 工作正常：

$ go build -buildmode=c-archive

但是针对它的编译失败了：

$ gcc -o gohttp-c examples/c/main.c gohttplib.a -lpthread
Undefined symbols for architecture x86_64:
  "_CFArrayGetCount", referenced from:
      _FetchPEMRoots in gohttplib.a(000003.o)
  "_CFArrayGetValueAtIndex", referenced from:
      _FetchPEMRoots in gohttplib.a(000003.o)
  "_CFDataAppendBytes", referenced from:
      _FetchPEMRoots in gohttplib.a(000003.o)
  "_CFDataCreateMutable", referenced from:
      _FetchPEMRoots in gohttplib.a(000003.o)
  "_CFDataGetBytePtr", referenced from:
      _FetchPEMRoots in gohttplib.a(000003.o)
      __cgo_6dbb806e9976_Cfunc_CFDataGetBytePtr in gohttplib.a(000003.o)
     (maybe you meant: __cgo_6dbb806e9976_Cfunc_CFDataGetBytePtr)
  "_CFDataGetLength", referenced from:
      _FetchPEMRoots in gohttplib.a(000003.o)
      __cgo_6dbb806e9976_Cfunc_CFDataGetLength in gohttplib.a(000003.o)
     (maybe you meant: __cgo_6dbb806e9976_Cfunc_CFDataGetLength)
  "_CFRelease", referenced from:
      _FetchPEMRoots in gohttplib.a(000003.o)
      __cgo_6dbb806e9976_Cfunc_CFRelease in gohttplib.a(000003.o)
     (maybe you meant: __cgo_6dbb806e9976_Cfunc_CFRelease)
  "_SecKeychainItemExport", referenced from:
      _FetchPEMRoots in gohttplib.a(000003.o)
  "_SecTrustCopyAnchorCertificates", referenced from:
      _FetchPEMRoots in gohttplib.a(000003.o)
  "_kCFAllocatorDefault", referenced from:
      _FetchPEMRoots in gohttplib.a(000003.o)
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [example-c] Error 1

这是在 OS X 10.9.5 上使用来自 Go github 存储库 (38e3427) 的最新版本。我知道 Go 1.5 还没有发布，也不能保证它能正常工作，但我这样做是为了教育目的，我怀疑我遗漏了什么。

相关版本：

$ ld -v
@(#)PROGRAM:ld  PROJECT:ld64-241.9
configured to support archs: armv6 armv7 armv7s arm64 i386 x86_64 x86_64h armv6m armv7m armv7em
LTO support using: LLVM version 3.5svn
$ gcc --version
Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/usr/include/c++/4.2.1
Apple LLVM version 6.0 (clang-600.0.57) (based on LLVM 3.5svn)
Target: x86_64-apple-darwin13.4.0
Thread model: posix

Answer 1

原来 OSX/darwin 上存在这个问题。要解决这个问题，我们需要向 gcc 链接命令添加 -framework CoreFoundation -framework Security 选项。最终命令如下所示：

$ gcc -o gohttp-c examples/c/main.c gohttplib.a \
      -framework CoreFoundation -framework Security -lpthread

Go 的未来版本可能会删除此要求。在此处对此问题进行更多讨论：https://github.com/golang/go/issues/11258

使用 Go 1.5 buildmode=c-archive 和 net/http。从 C 链接的服务器

Using Go 1.5 buildmode=c-archive with net/http.Server linked from C

c

linker

ld

go

gccgo