Question

如何在QT中写C函数？

Answer 1

/********MyButton.h*********/

#ifndef MYBUTTON_H_
#define MYBUTTON_H_

#include<iostream>
#include <QtGui/QPushButton>
#include <QtGui/QWidget>

class MyButton : public QPushButton
{
Q_OBJECT
public:
MyButton(const QString & text, QWidget * parent);
~MyButton();
public:
void setLed(int argc, char *argv[]);

public slots:
void sendButtonText();
private:
signals:
void isClickButton(const QString &text);
};

#endif

[cpp] view plain copy
/**********MyButton.cpp************/

#include "MyButton.h"

extern "C"{

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/ioctl.h>
#include<sys/types.h>
#include<sys/stat.h>
#include<fcntl.h>

void MyButton::setLed(int argc, char *argv[]){
int on;
int led_number;
int fd;
if (argc != 3 || sscanf(argv[1], "%d", &led_number) != 1 || sscanf(argv[2],"%d", &on) != 1 ||
on < 0 || on > 1 || led_number < 0 || led_number > 3) {
fprintf(stderr, "Usage:\n");
fprintf(stderr, "\t led led_number on|off\n");
fprintf(stderr, "Options:\n");
fprintf(stderr, "\t led_number from 0 to 3\n");
fprintf(stderr, "\t on 1 off 0\n");
exit(1);
}
fd = open("/dev/led", 0);
if (fd < 0) {
perror("open device /dev/led");
exit(1);
}
ioctl(fd, on, led_number);
::close(fd); //请注意，此处如果要调用C语言库中的close()一定要加上“::"，否则程序将到当前类的作用域中寻找close()方法，导致不明错误。
}
}

MyButton::MyButton(const QString &text,QWidget *widget)
:QPushButton(text,widget)
{
connect(this,SIGNAL(clicked()),this,SLOT(sendButtonText()));
}

MyButton::~MyButton()
{
}

void MyButton::sendButtonText(){
emit isClickButton(this->text());
char open_1[]="1";
char open_2[]="1";
char open_3[]="1";

char *o1=open_1;
char *o2=open_2;
char *o3=open_3;

char close_1[]="1";
char close_2[]="1";
char close_3[]="0";

char *c1=close_1;
char *c2=close_2;
char *c3=close_3;

char *open[]={o1,o2,o3};
char *close[]={c1,c2,c3};

QString *str=new QString(this->text());
if((str->compare("mb1"))==0){
std::cout<<"mb1 is clicked!\n";
setLed(3,open);
}
if((str->compare("mb2"))==0){
std::cout<<"mb2 is clicked!\n";
setLed(3,close);
}

}