小编sub*_*ngh的帖子

我在mac机器上使用OS 10.9.我想知道我正在使用的gcc版本.所以我尝试gcc --version了终端,结果如下:

$ gcc --version
Configured with: --prefix=/Applications/Xcode5-DP.app/Contents/Developer/usr --with-gxx-include-dir=/Applications/Xcode5-DP.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/usr/include/c++/4.2.1
Apple LLVM version 5.0 (clang-500.1.58) (based on LLVM 3.3svn)
Target: x86_64-apple-darwin13.0.0
Thread model: posix

在输出中,没有与gcc相关的细节,但clang就在那里.我很困惑gcc命令是否执行clang或gcc(gnu).

我收到与err_sys()此代码相关的错误:

#include <stdio.h>
#include <sys/socket.h>
#include <netinet/in.h>
int main()
{
    int sockfd;

    if ((sockfd=socket(AF_INET,SOCK_STREAM,0))<0)
        err_sys("can't create socket");

    close(sockfd);
    return 0;
}

我收到链接器错误:

/tmp/cciuUVhz.o: In function `main':
getsockopt.c:(.text+0x38): undefined reference to `err_sys'
collect2: ld returned 1 exit status

功能在哪里err_sys()定义？

有人可以提供从goroutine返回的澄清值.来自goroutine的返回值是否存储在桩上.

例如:

// function getNumber returns the "int i" and we can't use this returned value
// because this function is invoked as goroutine.
// We know that, to communicate between main and goroutine one could
// use the channel ( chan <- i), but I am interested to know about
// the use of return i in goroutine. Is it possible to get/ use this 
// returned value.
func getNumber(i int) int {
    return i   
    }

func main() { …

我是我的UIView课的子类.Xcode(我使用的是4.6.3)自动生成的代码说,

/*
// Only override drawRect: if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
- (void)drawRect:(CGRect)rect
{
    // Drawing code
}
*/

它在我的脑海中提出了几个问题:

1)为什么空的实现drawRect:会在动画期间导致不良性能.

2)我什么时候应该实施drawRect:.

3)如果我正在实施,drawRect:那么应采取什么措施作为最佳实践的预防措施.

我正在尝试编写一个函数Map,以便它可以处理所有类型的数组.

// Interface to specify generic type of array.
type Iterable interface {
}

func main() {
    list_1 := []int{1, 2, 3, 4}
    list_2 := []uint8{'a', 'b', 'c', 'd'}
    Map(list_1)
    Map(list_2)
}

// This function prints the every element for
// all []types of array.
func Map(list Iterable) {
    for _, value := range list {
        fmt.Print(value)
    }
}

但它会抛出编译时错误.

19: cannot range over list (type Iterable)

错误是正确的,因为range需要数组,指向数组,切片,字符串,映射或通道的指针允许接收操作,此处类型为Iterable.我认为我面临的问题是,将参数类型转换Iterable为数组类型.请建议,我如何使用我的函数来处理通用数组.

我正在关注以下博客来配置我的golang环境(OS-X机器):

http://webapp.org.ua/dev/intellij-idea-and-go-plugin/

但是,每当我尝试添加go sdk(安装在/ usr/local/go)时,它就会显示为SDK的空白选择.

如果我错过了什么,请建议我.

我是Iphone编程的初学者.我正在尝试编译(ubuntu).

#import <Foundation/Foundation.h>

int main (void)
 {
  NSLog (@"Executing");
  return 0;
 }

我编译了它但得到了跟随错误

   subhash@subhash-Lenovo-G570:~/grit/iphone/mac$ gcc -lgnustep-base -lpthread -lob
  jc -lm -I/usr/local/include/GNUstep -I/usr/include/GNUstep -fconstant-string-cla
  ss=NSConstantString hello.m -o hello
  In file included from /usr/include/GNUstep/Foundation/NSClassDescription.h:30:0,
                  from /usr/include/GNUstep/Foundation/Foundation.h:50, 
                  from hello.m:1:
  /usr/include/GNUstep/Foundation/NSException.h:42:2: error: #error The current se
  tting for native-objc-exceptions does not match that of gnustep-base ... please 
  correct this.

我按照http://ubuntuforums.org/showthread.php?p=5593608作为参考.

我评论了NSException.h的#error指令,问题解决了.现在我收到了新的错误.

/tmp/ccQlI9wJ.o: In function `main':
        hello.m:(.text+0x11): undefined reference to `NSLog'
        /tmp/ccQlI9wJ.o: In function `__objc_gnu_init':
        hello.m:(.text+0x2a): undefined reference to `__objc_exec_class'
        /tmp/ccQlI9wJ.o:(.data+0x40): undefined reference …

我试图找到将黑色主题设置为我新安装的Android工作室的方法,但我没有获得成功.

我见过类似的问题,但是对于Windows(我没有获得设置选项).

请告诉我如何在mac机器上做同样的事情.

我试图从下面的例子中提供谈话了解java8的尾递归.

@FunctionalInterface
public interface TailCall<T> {
    TailCall<T> apply();

    default boolean isComplete() {
        return false;
    }

    default T result() {
        throw new Error("not implemented");
    }

    default T get() {
        return Stream.iterate(this, TailCall::apply).filter(TailCall::isComplete)
                                                .findFirst().get().result();
    }
}

使用TailCall的实用程序类

public class TailCalls {
    public static <T> TailCall<T> call(final TailCall<T> nextcall) {
        return nextcall;
    }

    public static <T> TailCall<T> done(final T value) {
        return new TailCall<T>() {
            @Override
            public boolean isComplete() {
                return true;
            }

            @Override
            public T result() {
                return value;
            } …

我正在关注编写我的网络应用程序的golang教程.我正在修改教程页面中的代码,以便我可以执行保存的页面作为go代码(类似于go playground).但是当我尝试使用os/exec包执行保存的go文件时,它会抛出以下错误.

exec:"go run testcode.go":在$ PATH中找不到可执行文件

以下是我修改过的代码:

// Structure to hold the Page
type Page struct {
    Title  string
    Body   []byte
    Output []byte
}

// saving the page
func (p *Page) save() { // difference between func (p *Page) and func (p Page)
    filename := p.Title + ".go"
    ioutil.WriteFile(filename, p.Body, 0777)
}

// handle for the editing
func editHandler(w http.ResponseWriter, r *http.Request) {
    title := r.URL.Path[len("/edit/"):]

    p, err := loadPage(title)

    if err …

我想从 C 函数空间调用 go func，但程序抛出构建错误。

示例.go

package main

/*
#include "test.c"
*/
import "C"
import "fmt"

func Example() {
    fmt.Println("this is go")
    fmt.Println(C.GoString(C.myprint(C.CString("go!!"))))
}

// export receiveC              (remove the extra space between // and export)
func receiveC(msg *C.char) {
    fmt.Println(C.GoString(msg))
}

func main() {
    Example()
}

测试.c

#include <stdio.h>

extern void receiveC(char *msg);

char* myprint(char *msg) {
    receiveC(msg);  // calling the exported go function
    return msg;     
    }

当我执行命令来运行/构建（go build或go run example.go或go build example.go）程序时，它会抛出错误：

# …

我正在尝试使用代码片段来理解要理解的collect方法IntStream.我试图结果Hashmap <string, Integer>.

    IntStream.range(0, 4).collect(
            HashMap::new,
            result, t -> result.put("test", somearray.get(t)),
             result -> result.putall()
            );

但汇编抱怨,can't find symbol variable result.

按我的理解,我需要传递(t, value) -> ...给accumulatore,但我无法理解编译问题,以及使用组合(第三个参数)的.

我试图使用这个SOAP客户端调用SOAP服务,但它不适合我.请帮我.如何使用Phonegap发送和接收XML SOAP？