去+ CGO和链接

Question

我想用下面的C作为Go的CGO：

#include <X11/extensions/scrnsaver.h> 

main() { 
    XScreenSaverInfo *info = XScreenSaverAllocInfo(); 
    Display *display = XOpenDisplay(0); 

    XScreenSaverQueryInfo(display, DefaultRootWindow(display), info); 
    printf("%u ms\n", info->idle); 
} 

构建具有：

gcc -o idle printXIdleTime.c -lX11 -lXss 

我重新写了Go的CGO代码：

package tools 

// #cgo pkg-config: x11 
// #include <X11/extensions/scrnsaver.h> 
import "C" 

func GetIdleTime() (idleTime uint32) { 
    var info *C.XScreenSaverInfo 
    var display *C.Display 

    info = C.XScreenSaverAllocInfo() 
    display = C.XOpenDisplay(0) 

    defaultRootWindow := C.XDefaultRootWindow(display) 

    C.XScreenSaverQueryInfo(display, defaultRootWindow, info) 
    idleTime = info.idle 

    return 
} 

试图编译：

go build -gccgoflags="-lXss -lX11" 

但是我得到的链接错误：

/tmp/go-build076004816/opensource.stdk/lib/tools/_obj/x11.cgo2.o: In function _cgo_c0e279f6f16e_Cfunc_XScreenSaverAllocInfo': ./x11.go:52: undefined reference to XScreenSaverAllocInfo' /tmp/go-build076004816/opensource.stdk/lib/tools/_obj/x11.cgo2.o: In function _cgo_c0e279f6f16e_Cfunc_XScreenSaverQueryInfo': ./x11.go:65: undefined reference to XScreenSaverQueryInfo' collect2: error: ld returned 1 exit status

我到底做错了什么？

Answer 1

这就是我如何构建它。请注意0​​这一行可能是你错过的。我必须做一些其他更改才能构建。它似乎在我的Linux机器上返回正确的答案！

package tools 

// #cgo LDFLAGS: -lXss -lX11 
// #include <X11/extensions/scrnsaver.h> 
import "C" 

func GetIdleTime() (idleTime uint32) { 
    var info *C.XScreenSaverInfo 
    var display *C.Display 

    info = C.XScreenSaverAllocInfo() 
    display = C.XOpenDisplay(nil) 

    defaultRootWindow := C.XDefaultRootWindow(display) 

    C.XScreenSaverQueryInfo(display, C.Drawable(defaultRootWindow), info) 
    idleTime = uint32(info.idle) 

    return 
} 

Answer 2

注意，这可能与本机X Go Binding和屏幕保护程序的扩展来完成：

package main 

import (
    "fmt" 
    "log" 

    "github.com/BurntSushi/xgb" 
    "github.com/BurntSushi/xgb/xproto" 
    "github.com/BurntSushi/xgb/screensaver" 
) 

func main() { 
    X, err := xgb.NewConn() 
    if err != nil { 
     log.Fatal(err) 
    } 

    if err = screensaver.Init(X); err != nil { 
     log.Fatal(err) 
    } 

    root := xproto.Setup(X).DefaultScreen(X).Root 
    info, err := screensaver.QueryInfo(X, xproto.Drawable(root)).Reply() 
    if err != nil { 
     log.Fatal(err) 
    } 

    fmt.Printf("Idle: %d\n", info.MsSinceUserInput) 
} 

输出：

[andrew@Liger go] go run xscreensaver_idle.go 
Idle: 1040