if condition in linux

from:http://blog.csdn.net/fengge8ylf/article/details/6896380 Author: Wang Dong 1.1 What is conditional variable and condition wait. To put it simply: A condition variable (condition variable) is a mechanism for synchronizing with global variables

POSIX condition Variables int Pthread_cond_init (pthread_cond_t *cond, pthread_condattr_t *cond_attr); int Pthread_cond_destroy (pthread_cond_t * cond); int pthread_cond_wait (pthread_cond_t *cond, pthread_mutex_t *mutex); int

Linux mutexes, condition variables, and semaphores from http://kongweile.iteye.com/blog/1155490Blog Category: Linux Sem_init: Initializes the semaphore sem_t, the initial value of the semaphore can be specified when initializing, and

If condition judgment of Linux shell script, linuxshellIF condition judgment1. Basic Syntax:If [command]; thenStatements that meet this conditionFi 2. Extended Syntax: If [command]; then Statements that meet this condition Elif [command];

linux--linux mutexes, condition variables, and semaphoresfor multithreaded programming, the most important thing to note is the shared data, because there is no way to know which thread will operate on it, or which thread will run first and which

From: http://m.jb51.net/article/56553.htm This article mainly introduced the shell script if condition judgment and the judgment condition summary, this article first gave the IF condition judgment the grammar, then gave the commonly used judgment

If condition judgment1. Basic syntax:if [command]; ThenStatements that meet the criteria for executionFi2. Extended syntax:if [command];thenStatements that meet the criteria for executionelif [Command];thenStatements that meet the criteria for

Reprint Please specify source: http://blog.csdn.net/suool/article/details/38582521.Basic concepts and principlesMutexes can resolve mutually exclusive access to resources, but in some cases, mutual exclusion does not solve the problem, such as two

Conditional statements are used to perform different actions based on different conditions. Conditional statement Usually when writing code, you always need to perform different actions for different decisions. You can use conditional statements

I. Shell Condition Statement (if usage) If statement structure [if/then/Elif/else/FI] If condition test statement Then Action [Elif Condition Action Else Action ] Fi If you are not clear about the conditional test statement, refer to: