unix programming book

Copyright statement: original works can be reproduced. During reprinting, you must mark the original publication, author information, and this statement in hyperlink form. Otherwise, legal liability will be held. Http://blog.csdn.net/mayongzhan-ma yongzhan, myz, mayongzhan Address: http://codepoets.co.uk/book-review-object-orientated-programming-php5-hasin-hayder-packt-publishing Suddenly I received an emai

This book I read the electronic version, feel good, a total of 20 chapters, the book is as follows:This book is designed to enable you to learn Python as quickly as possible so that you can write programs that work correctly-games, data visualizations, and WEB applications-while mastering basic programming knowledge th

) { Continue; } for(i =1; i i) {if(Client[i].fd 0) CLIENT[I].FD=CONNFD; Break; } if(i = =Open_max) {printf ("Too many clients"); Exit (0); } client[i].events=Pollrdnorm; if(I >Maxi) {Maxi=i; } if(--nready 0 ) Continue; } for(i =1; i i) {if((SOCKFD = CLIENT[I].FD) 0) { Continue; } if(Client[i].revents Pollrdnorm |Pollerr) { if((n = Read (SOCKFD, buf, MAXLINE)) 0

at system startup, or if you can shut down these programs correctly when the system restarts, you need to create a run-level script.Run levelDetermine the current runlevel: Who-r (Linux system: RunLevel The first value is the previous runlevel of the system, and the second value is the current runlevel.) ）InittabThe init process starts during the system startup process, which uses the Inittab configuration file to see which services need to be started and which runlevel to enter.Inittab format:

One, wait () functionWhen you call the Wait () function in a process(1) If all of its subroutines are still being executed, the blockage(2) Assume that a child process has been terminated. Waits for the parent process to get its terminating state.(3) If there are no child processes, an error is returned.In the following instance. Call Wait () in the parent process, assuming that the child process has not completed yet, and then calls itself into the blocked state.Wait for the child process to fi

Process ControlPS auxPS AXJPS AXFPS AXMI. Process identifierspid_t---->long intUnique identity of the process0 calling process (kernel)1init process (user-state ancestor process for all processes)Getpid (2);Getppid (2);Status of the processs interruptible sleep stateR Run StateD Non-disruptive sleep stateT stop Statex termination stateZ Zombie StateProcess priorityS conversation leaderL MultithreadingN Low-priority+ in the foreground process groupTwo. Fork (2)Differences between parent and child

: As a process accounting processing, it will record some of the relevant information about the process. 7, process scheduling: about the execution of a process and A nice value, you can change the schedule of a process by changing the value.Process Relationship: 1, Process group: about process relations, from the most basic process to understand, a number of processes can constitute a process group, which explains the creation of process groups, set up, return and other operational functions o

One, wait () functionWhen you call the Wait () function in a process(1) If all of its subroutines are still running, block(2) If a child process is terminated, wait for the parent process to get its terminating state.(3) If there are no child processes, an error is returned.In the following instance, wait () is called in the parent process, and if the child process has not finished running, it calls itself into a blocking state.After the child process has finished running, the child process's re

refer to any character or string except the character $, ', \ \.A single quotation mark is similar to a double quote, but a single quotation mark and its internal value are used as a new string if the special meaning is masked.boy= ' Boy ' echo, like ' $BOY ', ' echo ' like ' $BOY 'The contents of the two echo outputs are not the same, and the previous ECHO has a pair of single quotes.Anti-quote: The shell takes the contents of the backslash as a system command and executes it.Backslash: A back

1 exit function and _exit function#include void exit (int status)void _exit (int status)The difference between these two functions is that the exit function performs cleanup before entering the kernel (cleanup I/O buffering), and the_exit function goes directly into the kernel 2 atexit function, register function, execute at exit int atexit (void (* func) (void));The functions that are registered are called termination handlers, which are called in the reverse order of registration, and are cal

limited amount of information in the first two modes of communication, the process with Write permission can add new message to message queue according to certain rules, and the process with Read permission to message queue can read the message from Message queue.　　Semaphore (Semaphore): primarily as a means of synchronization and mutual exclusion between processes and between different threads of the same process. Shared memory: This can be said to be the most useful way to communicate between

Initializationint pthread_cond_destory Destroyint pthread_cond_wait Release the lock, the thread waits until the condition changes (wait for the condition to change, must already hold the lock)int pthread_cond_timewait and similar above, just have a timeout do not waitint pthread_cond_signal sends a signal to change the condition, at least to wake up aint Pthread_cond_broadcast wakes all the threads waiting for the conditionBarrierAllow each thread to wait until all of the cooperating threads r

: thread: The identifier of the waiting thread.Thread_return: User-defined pointer to store the return value of the waiting thread (not a null value);function return value: Success: 0Failed:-1#include Running result: g++ linux1.cpp-o pthread-lpthread[Email protected] linux_chen]$./pthreadThis is pthread1!This is pthread2!This is pthread2!This is pthread2!This is pthread1!This is pthread1! Copyright NOTICE: This article for Bo Master original article, without Bo Master permission not reproduced.

and Group ownerThe owner of the file is identified by St_uid and the group owner is identified by St_gid4 The user ID for creating a file is set to a valid user ID for the process, the group ID may be a valid group ID for the process, or it may be a valid group ID for the directory where the file resides5 Access functions to test the actual user ID for a file#include int access (constChar* pathname,int mode);Successful return 0, failure return-1Value of ModeR_OK, W_OK, X_OK, F_OK (test file exi

int sigsuspend (const sigset_t * sigmask);The signal mask Word setting for the process is specified by Sigmask.The process is suspended until a signal is captured. Assuming a signal is captured, Sigsuspend returns, and the new high-screen word of the process is set to its previous value.Cases:#include "apue.h" static void Sig_int (int), void pr_mask (const char *STR)//print the current blocked signal {sigset_t sigset; int errno_save; Errno_save = errno; /* We can be called by signal hand

(SERVADDR)) 0) {fprintf (stderr,"Connect error\n"); Exit (1); } process (stdin, SOCKFD); Exit (0);}/*server_tcp.c*/#include#includestring.h>#include#include#include#include#include#includeinch.h>#defineMAXLINE 4096#defineListenq 1024#definePORT 12345voidProcessintsockfd) {ssize_t n; CharBuff[maxline+1]; while((n = read (SOCKFD, buff, MAXLINE)) >0{write (SOCKFD, buff, n); }}intMainintargcChar*argv[]) { intLISTENFD, CONNFD; structsockaddr_in servaddr, cliaddr; pid_t pid; LISTENFD=

Time-----Last visitedModify time-----Last modified content (LS-L)Change time-----Last modification of the attribute information (inode)8. Read the CatalogueOpendir (3);Readdir (3);Closedir (3);Glob (3);9. Understandmkdir (2);RmDir (2);Remove (3);//unlink (2)/rmdir (2);Rename (2);Chown (2);Fchown (2);Lchown (2);Umask (2);chmod (2);Fchmod (2);Link (2);Unlink (2);System data files and information1./etc/passwdMans 5 passwdGetpwuid (3);Getpwnam (3);2./etc/groupMans 5 GroupGetgrgid (3);Getgrnam (3);3

C Standard IO---io with cacheAdvantage:With cache (merge system calls)Disadvantages:Low real-time availabilityType of cache:Row cache: stdin stdout (buffer is size)Full cache: FileNo cache: stderr1. FlowThe identity of the open file2.FILE typestruct type:File descriptorThe address of the bufferSize of the cacheError ID3. Opening of the streamfopen (3);errno Global VariablesDefined macros:/usr/include/asm-generic/errno-base.h/usr/include/asm-generic/errno.hStrerror (3);Perror (3);4. Stream operat

achieve synchronization structSembuf p = {1,-1,0};structSembuf v = {0,1,0}; while(1){//client read the data and determine if the data came from the server is quit, if the direct program ends for quitSemop (sem_id, p,1);printf("ser:>%s\n", addr);if(strncmp(Addr,"Quit",4) ==0){ Break; }//The data read is not quit, the client writes the data "at this point the value of signal number 1th is 0, the client's read operation is blocked" printf("Cli:>"); Gets (addr);//If the data sent by the

. File status flags (such as read, write, non-blocking, etc.)2. Current file offset3. Pointers to V-node table entries(3) V-node table entryEach open file has a V-node structure.Functions Pread and Pwritebelongs to atomic operations.Do not update the current file offsetfunction DUP and dup2To copy an existing file descriptorint dup (int fd)int dup2 (int fd, int fd2)A new file descriptor returned by the function shares the same file table entry as the parameter FDInvoke DUP (FD) equivalent to Fcn