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...
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...
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...
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...
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 */ ...
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 ...
This table shows how Simulink infers a global variable from custom code. Example CodeSimulink Scope double data; void foo(void) { int temp = data; } Global variable data only reads the variable data. Available scopes are: Input (default) Global double data; void bar(void) { data = 0; ...