litespeed fork

Transferred from: http://blog.csdn.net/koches/article/details/7787468A wonderful thing about a fork call is that it is called only once, but it can return two times, and it may have three different return values:1) In the parent process, fork returns the process ID of the newly created child process;2) in the sub-process, fork returns 0;3) If an error occurs,

);//return Value: The parent process ID of the calling process5uid_t Getuid (void);//return value: The actual user ID of the calling process6uid_t Geteuid (void);//return value: The valid user ID of the calling process7gid_t Getgid (void);//return value: The actual group ID of the calling process8gid_t Getegid (void);//return value: The valid group ID of the calling processThe above 6 functions, if executed successfully, return the corresponding ID value, or 1 if it fails. In addition to the pro

function, the source process is completely substituted by the new program, and the new program executes from its main function. Because calling exec does not create a new process, the process ID before and after does not change. exec just replace the body, data, heap, and stack segments of the current process with another new program . In particular, file descriptors that have been opened in the original process will remain open in the new process unless their "Close flag on Execution" (Close o

The C language under Linux can use fork () to establish a child process.The fork function returns two values, and returns 0 for the child process; The parent process, which returns the child process ID. So withif (fork () ==0){The code snippet executed by the child process;}Else{The code snippet executed by the parent process;}Two. The

A new process created by Fork is called a subprocess (child process). The function is called once, but returns two times. The difference of two returnsis that the return value of the child process is 0, and the return value of the parent process is the process ID of the new process (child process). The reason for returning the child process ID to the parent process is that because there can be more than one child process for a process, there is no fun

The so-called process control is that the system uses a number of specific functions of the program to create processes, undo processes, and complete the process of transitions between various states,so as to achieve multi-process efficient concurrent execution and coordination of resource sharing purposes. Process Control is an important task of process management and processor management. 1. Fork () Create processIn Linux systems, the first process

resource management, and the thread is the smallest unit of program execution.In a Linux system, POSIX threads can "be considered" as a lightweight process, pthread_create create threads and fork creation processes are created by invoking the __clone function in the kernel, except when the option to create a thread or process is different. For example, whether to share virtual address space, file descriptors, and so on.Fork and multithreadingWe know

Summary of linux multi-process (fork usage)-Linux general technology-Linux programming and kernel information. The following is a detailed description. Original: lobbve223 Simply put, a process represents a State in one execution process of an executable program. The management of processes by the operating system is typically completed through the process table. Each table entry in the table records a process in the current operating system. For a s

The following is an instance of the fork function. [Cpp]# Include # Include # Include Int glob = 6;Char buf [] = "a write to stdout \ n ";Int main (void){Int var;Pid_t pid;Var = 88;If (write (STDOUT_FILENO, buf, sizeof (buf)-1 )! = Sizeof (buf)-1)Printf ("error: write error \ n ");Printf ("before fork \ n ");If (pid = fork () Printf ("error:

A binary tree is a tree structure with a maximum of two subtrees per node. The subtree is often referred to as the left subtree and the right subtree (subtree). Binary trees are often used to implement a two-fork search tree and a two-fork heap.Traversal ordertraversal is one of the most basic operations of the tree, so-called traversal of the binary tree, that is, according to a certain rules and order all

1. What is a clue two fork tree?There must be n+1 null pointer fields in the two-linked list with n nodes , so you can use these null pointer fields to hold pointers to the forward and subsequent nodes in some sort of traversal order that point to the node, a pointer to the forward and subsequent nodes called a "clue", Plus a clue to the two-linked list called the Clue list, the corresponding two-fork tree

1. Basic ConceptsIn chained storage, it is found that there are a large number of NULL pointers in the two-linked list, and it is more convenient to use some binary tree operation algorithms If these null pointers are used to point to their direct precursor or subsequent pointers. The clue of the binary tree is to speed up the discovery of the node precursor and the subsequent speed.In a two-fork tree with n nodes, there is a n+1 null pointer. Each le

I. copying process images 1,ForkFunction Introduction This system call mainly copies the current process and creates a new table item in the Table. Many attributes of the new table item are the same as those of the current process. The new process is almost identical to the original process.CodeBut the new process has its own data space, environment, and file descriptor. 2TYPICAL USEForkCode snippet: Pid_t PID; PID = Fork (); Switch (PID ){

A tree is a very important data structure, and a binary tree is the most basic form of a tree. Like other advanced data structures, such as binary search tree, balanced binary tree, AVL tree, red black tree, splay tree (stretching tree), flute Karlshu, treap, SBT tree are all based on two fork trees.Properties Each node in the tree has 0-2 child nodes, and each child node becomes the root of a subtrees tree. The number of edges in the tree is th

PS: Every blog but in order to record the process of learning, and reflect on the summary, if there are errors, but also to correct .Function prototype: extern __pid_t fork (void) __thrownl;The function is included in the header file unistd.h.Gaze in the source file:/* Clone The calling process, creating an exact copy. Return-1 for errors, 0 to the new process,And the process ID of the new process to the old process. */

Recently looking at the communication between the processes, see the fork () function, although used before, this time after thinking deepened understanding. The summary is as follows: 1. The function itself (1) header file #include #include (2) Function prototype pid_t fork (void);(pid_t is a macro definition whose essence is int is defined in #includeReturn value: Returns two values if a successful

Fork-Fork Assistant Computer Download installation tutorial come on. If you want to know how to use the fork-Fork Assistant computer, you can see the following Oh, fork Assistant is the most popular game modifier, on the computer is also available, the steps below. The firs

之前只是了解到linux中的fork函数是用来创建进程，并没有太多的去学习，这里学习记录如下。Writing is not easy, reprint need to indicate the source: http://blog.csdn.net/jscese/article/details/44401389 This article from the "Jscese" blog!Defined:Explanation from the Encyclopedia: thefork function divides the running program into 2 (almost) identical processes, each initiating a thread that executes from the same location in the code. The threads in both processes continue to execute, as if two

0. order 1. basic Content 1) Process Composition: 2) after the fork function is called, the system does the following work: 2. function details 1) function prototype 2) function 3) description 3. summary: 0. OrderThe fork function is a function used to create a process in Linux. It is also the only function used to create a process. Therefore, I learned the basics of

a tree: the maximum degree of a node in a tree. level : The level of the root node is 1, the rest of the node is equal to the level of the parent node of the node plus 1.height of the tree : The maximum level of nodes in the tree.unordered Tree : If the order between the nodes in the tree is unimportant, you can swap positions.ordered Tree : If the order between the nodes in the tree is important, the position cannot be exchanged.Forest : consisting of 0 or more disjoint trees. Add a root to th