condition_variable 类型的对象始终使用 unique_lock<mutex> 等待(有关可与任何类型的可锁定类型一起使用的替代方法,可参见 condition_variable_any)。 // condition_variable example #include <iostream> // std::cout #include <thread> // std::thread #include <mutex> // std::mutex, std::unique_lock ...
condition_variable condition_variable 类是同步原语,能用于阻塞一个线程,或同时阻塞多个线程,直至另一线程修改共享变量(条件)并通知 condition_variable 。 有意修改变量的线程必须 获得std::mutex (常通过 std::lock_guard ) 在保有锁时进行修改 在std::condition_variable 上执行 notify_one 或 notify_all(不...
Only one of the two expressions (Exp2 or Exp3) is evaluated based on the condition. Example 1: Basic Conditional Operator usage The conditional operator compares two values and assigns the larger one to a variable. Code: #include <stdio.h> int main() { int a = 10, b = 20; // Use...
首先说明如何修改或创建一个环境变量,使用set(ENV{<variable>} <value>)指令用以声明,使用unset(ENV{<variable>})来清除某一个环境变量,其中ENV表示环境变量标志性前缀,variable指变量名称,value则为变量值,需要注意的是设定或读取环境变量时,都通过ENV前缀来访问环境变量,读取环境变量值时,要在ENV前加$符号;但if...
option(<variable> "<help_text>" [value]) 使用样例: option(TEST_DEBUG "option for debug" OFF) (6) if…else[if]…endif 含义:这个不用详细介绍了,用法同编程语言中的控制语句 语法: if/else([<condition>]) 使用样例: if(WIN32) message(STATUS "inWindowsSystem") ...
char b; /* Wrong, variable with char type already exists */ char a, b; /* OK */ } 按顺序声明局部变量 i. 自定义结构和枚举 ii. 整数类型,更宽的无符号类型优先 iii. 单/双浮点 int my_func(void) { /* 1 */ my_struct_t my; /* First custom structures */ ...
In this example- We declare and initialize the year integer variable with the value 2024 inside the main() function. Then, we declare another variable called isLeapYear and use the ternary operator to assign a value to the variable. In that- The outer condition uses the logical OR operator...
Example: #include <stdio.h> int main() { int num = 10; if (num > 5) { printf("The number is greater than 5.\n"); } else { printf("The number is not greater than 5.\n"); } return 0; } In this example, the condition num > 5 is evaluated. Since the value of num is...
This example requires that you create the following variable. 展開表格 VariableData type MyCode Code 複製 MyCode := 'ABC'; CASE MyCode OF 'abc': MESSAGE('This message is not displayed.'); 'def': MESSAGE('This message is not displayed.'); ELSE MESSAGE('The value set does not match ...
Zero-crossing detection can be done only when the S-function is running at a continuous sample rate using a variable-step solver. The if statement uses ssIsVariableStepSolver, ssGetSampleTime, and ssGetOffsetTime to determine if this condition is met. If so, the method sets the number of ...