我正在尝试为共享内存对象运行程序。我的代码如下:
#include <stdio.h> /*adding standard input output library*/
#include <stdlib.h> /*standard library for four variable types, several macros, and various functions for performing general functions*/
#include <string.h> /*adding string library*/
#include <
我创建了一个函数来获取有关变量的类型信息。除了一种情况外,这个函数工作得很好。如果我传递一个未定义的变量,浏览器将不会执行任何代码并显示错误。职能如下:
function getType(v) {
if (typeof v === 'undefined')
return 'undefined';
else if (v === null) //typeof v will return object if it is null
return 'null';
else if (v instance
我正在处理一个C项目,在这个项目中我需要获取目录中的文件列表。我正在使用dirent.h,但在运行时遇到了一些问题,我正在Linux下构建该程序。
当我尝试构建这个程序时,我得到了以下错误
myClass:error: âDIRâ undeclared (first use in this function)
myClass:408: error: (Each undeclared identifier is reported only once
myClass:408: error: for each function it appears in.)
myClass:408: error:
我的编译器说: save是未声明的...我通过"FILE *save“声明了它
FILE *save
save = fopen ("filename.txt", "w");
while ( current != NULL )
{
fprintf (save, " %s %s %d", current -> name, current -> tel, current -> age);
current = current -> next;
}
在C++中,
how can I get the **receiver address** of the UDP packet which I have received using recvfrom. I know that it should be the same host on which I am receiving the packet, but I need to extract it from the received packet, in order to verify something. How can I do this?
我发现这样做的一个方法是:
int r =
我使用的是"S_ISDIR“和"S_ISREG”,但得到的错误是它们是未声明的。我试着在macOS中使用它(使用S_IFDIR和S_IFREG),它可以工作,但在linux终端上不起作用。
error: ‘S_ISDIR’ undeclared (first use in this function)
error: ‘S_ISREG’ undeclared (first use in this function); did you mean ‘S_ISDIR’?
struct stat s;
if(stat(fileName, &s) == 0 )
{
我经常看到JavaScript代码以这样的方式检查未定义的空值:
if (typeof input !== "undefined") {
if ( input != null ) {
// do stuff
}
}
但是我认为它看起来太简单了,不太优雅,我想提供下一段代码:
// just have taken from my own code
setCamera: function( camera, scene, vector3 ) {
if ( !~[ undefined, null ].indexOf( camera ) &&a