go - 如何使用cgo静态链接go中的c库？

Question

因此，小组中有很多建议您可以随时进行的工作(尽管不在cgo文档中):

package bridge

import "fmt"

// #cgo CFLAGS: -I/Users/doug/projects/c/go-bridge/include
// #cgo LDFLAGS: /Users/doug/projects/c/go-bridge/build/libgb.a
// #include <junk.h>
import "C"

func Run() {
  fmt.Printf("Invoking c library...\n")
  C.x(10)
  fmt.Printf("Done\n")
}

但是，它似乎不起作用:

/var/folders/.../bridge.a(bridge.cgo2.o)(__TEXT/__text): x: not defined

使用动态库，这似乎很好用，并检查生成的文件，它实际上在其中带有符号“x”:

/var/folders/rg/hj4s3qlj3sz1d1b5p50ws0vc0000gn/T/go-build442792776/bridge/_obj/_cgo_.o:
0000000100001048 S _NXArgc 
0000000100001050 S _NXArgv 
0000000100001060 S ___progname 
0000000100000dc0 T __cgo_2d7eefe3d6d4_Cfunc_x
0000000100000da0 T __cgo_allocate 
0000000100000db0 T __cgo_panic
0000000100000000 T __mh_execute_header 
0000000100000d90 T _crosscall2
0000000100001058 S _environ
                 U _exit 
0000000100000d80 T _main
                 U _puts 
0000000100001000 s _pvars 
0000000100000de0 T _x                <------- Exists
                 U dyld_stub_binder 
0000000100000d40 T start

但显然只是bridge.cgo2.o中的标记:

/var/folders/rg/hj4s3qlj3sz1d1b5p50ws0vc0000gn/T/go-build442792776/bridge.a(bridge.cgo2.o):
0000000000000368 s EH_frame0
0000000000000000 T __cgo_2d7eefe3d6d4_Cfunc_x
0000000000000380 S __cgo_2d7eefe3d6d4_Cfunc_x.eh
                 U _x

我究竟做错了什么？

对于ref，c header :

int x(int y);

和代码:

#include <junk.h>
#include <stdio.h>

int x(int y) {
  printf("Hello World\n");
  return y;
}

-

编辑:

不，-L和-l也不起作用；实际上，在Google网上论坛上有一些具体讨论，认为该(-l / blah / blah.a)对cgo不起作用，实际上正确的语法是省略-l并仅列出.a文件...但是嘿，如果能用，我完全会用它。但事实并非如此:

dougs-mini:go doug$ go run test.go
# bridge
ld: library not found for -l/Users/doug/projects/c/go-bridge/build/libgb.a
collect2: ld returned 1 exit status
dougs-mini:go doug$ ls -l /Users/doug/projects/c/go-bridge/build/libgb.a
-rw-r--r--  1 doug  staff  872 25 May 14:02 /Users/doug/projects/c/go-bridge/build/libgb.a

详细版本:

dougs-mini:go doug$ go build -work -x test.go
WORK=/var/folders/rg/hj4s3qlj3sz1d1b5p50ws0vc0000gn/T/go-build354497708
mkdir -p $WORK/bridge/_obj/
cd /Users/doug/projects/c/go-bridge/go/src/bridge
/Users/doug/projects/go/go/pkg/tool/darwin_amd64/cgo -objdir $WORK/bridge/_obj/ -- -I/Users/doug/projects/c/go-bridge/include -I $WORK/bridge/_obj/ bridge.go
/Users/doug/projects/go/go/pkg/tool/darwin_amd64/6c -FVw -I $WORK/bridge/_obj/ -I /Users/doug/projects/go/go/pkg/darwin_amd64 -o $WORK/bridge/_obj/_cgo_defun.6 -DGOOS_darwin -DGOARCH_amd64 $WORK/bridge/_obj/_cgo_defun.c
gcc -I . -g -O2 -fPIC -m64 -pthread -fno-common -I/Users/doug/projects/c/go-bridge/include -I $WORK/bridge/_obj/ -o $WORK/bridge/_obj/_cgo_main.o -c $WORK/bridge/_obj/_cgo_main.c
gcc -I . -g -O2 -fPIC -m64 -pthread -fno-common -I/Users/doug/projects/c/go-bridge/include -I $WORK/bridge/_obj/ -o $WORK/bridge/_obj/_cgo_export.o -c $WORK/bridge/_obj/_cgo_export.c
gcc -I . -g -O2 -fPIC -m64 -pthread -fno-common -I/Users/doug/projects/c/go-bridge/include -I $WORK/bridge/_obj/ -o $WORK/bridge/_obj/bridge.cgo2.o -c $WORK/bridge/_obj/bridge.cgo2.c
gcc -I . -g -O2 -fPIC -m64 -pthread -fno-common -o $WORK/bridge/_obj/_cgo_.o $WORK/bridge/_obj/_cgo_main.o $WORK/bridge/_obj/_cgo_export.o $WORK/bridge/_obj/bridge.cgo2.o -l/Users/doug/projects/c/go-bridge/build/libgb.a
# bridge
ld: library not found for -l/Users/doug/projects/c/go-bridge/build/libgb.a
collect2: ld returned 1 exit status

值得注意的是，尝试像这样链接(使用-l)时失败是gcc链接失败的典型原因，因为您尝试合并一组目标文件。

即。这个:

gcc -I . -g -O2 -fPIC -m64 -pthread -fno-common -o ... -l/path/libgb.a

永远不会在gcc下编译；您必须像这样链接静态库:

gcc -I . -g -O2 -fPIC -m64 -pthread -fno-common -o ... /path/libgb.a

即。绝对不是我缺少-l或-L。

Answer 1

原来我的代码是100％罚款；它是Go 1.0的副本；在go 1.1下可以正常工作。
在go 1.0下，它不是。

(我知道回答我自己的问题有点la脚；但是下面的'use -L -l答案也不对；与之无关)。

GitHub上有一个可行的解决方案示例，适用于以后发现此问题的任何人:

https://github.com/shadowmint/go-static-linking

简而言之:

CGO_ENABLED=0 go build -a -installsuffix cgo -ldflags '-s' src/myapp/myapp.go

也可以看看:
https://github.com/golang/go/issues/9344