Tag: signals

Several advanced ways to play signals and slots in PyQt 5

The editor said: Signal and Slot are the core mechanisms in Qt and are also the mechanisms for communication between objects in PyQt programming. This article introduces several levels of PyQt 5 signals and slots. This article is selected from the book “PyQt5 Rapid Development and Practical Combat”. In Qt, every QObject object and all […]

Qt meta-object system, signals and slots, and events

Article directory meta-object system Basic concepts of meta-object system Meta-object system and reflection mechanism qobject_cast function Use reflection mechanism to obtain information about member functions of class objects QMetaMethon class QMetaObject class attribute system Signals and Slots Event delivery (or distribution) and processing Acceptance and Ignore of Events event filter Custom events and event sending […]

Qt signals and slots timers

Article directory 1 signals and slots 1.1 The concept of signals and slots 1.2 Application of signals and slots 1.3 Connection of signals and slots 1.4 Characteristics of signals and slots 1.5 Similar examples in life 1.6 Advantages of Signals and Slots 2 Use of signals and slots 2.1 Signals and slots of controls 2.2 […]

15｜Standard library: What is the relationship between signals and operating system soft interrupts?

I believe that when you first learned programming, you also wrote code similar to the following: #include <stdio.h> int main(void) { int x = 10; int y = 0; printf(“%d”, x / y); return 0; } It can be clearly seen that in the code here, the calculation result of the division expression x / […]

QT signals and slots_lambda expressions

Signals and Slots connect(sender,signal,receiver,slot)The parameters are all pointers sender: sender signal: signal receiver: receiver slot: Task to be executed (slot function) View common signal slots Search the corresponding class in the help document and find the signal/slot query. No signal may be in its base class Custom signals and slots Custom signal The essence of […]

STM32F407FFT identifies the frequency of sine wave signals

Table of Contents 1. Hardware equipment 2. General idea 1. Hardware Equipment Signal generator (for testing) or any other input signal, STM32F407ZGT6 series microcontroller, several DuPont wires, ST-Link programmer 2. General idea 1. ADC frequency samples the input signal, and DMA reads and transmits it. 2. Use the DSP library provided by the STM official […]

shell script loops and signals

Conditional judgment if condition 1; then COMMAND elif condition 2; then COMMAND else COMMAND(:): means pass does not execute any command fi Read user input and perform data judgment 1 echo -n “Enter your number: ” 2 read userinput 3 expr $userinput + 0 &>/dev/null 4 if [ $? -ne 0 ]; then 5 echo […]

Linux processes and signals: Exploration of normal and abnormal exit mechanisms

Directory title 1. Introduction 1.1 Basic concepts of Linux processes 1.2 The role and importance of signals 2. Normal Exit Mechanisms 2.1 Return from `main`) 2.2 Using the `exit()` Function to end the process (Using the `exit()` Function) 2.3 Normal Exit of Threads: `pthread_exit()` (Normal Exit of Threads: `pthread_exit()`) in conclusion 3. Exceptional Exit Mechanisms […]