C语言信号处理程序
#include signal.h
#include stdio.h
#include stdlib.h
#include unistd.h
void my_func(int sign_no)
{
if(sign_no==SIGINT)
printf(“I have get SIGINT\n”);
else if(sign_no==SIGTERM)
printf(“I have get SIGQUIT\n”);
}
int main()
{
printf(“Waiting for signal SIGINT or SIGTERM \n “);
printf(“process is %d\n “,getpid());
signal(SIGINT, my_func);
signal(SIGTERM, my_func);
while(1);
exit(0);
}
linux 平台就 用while阻塞就行
不知道你用的是什么平台?
linux下的C语言开发(信号处理)
姓名:冯成 学号:19020100164 学院:丁香二号书院
转自:
【嵌牛导读】本文将介绍linux下的C语言开发中如何进行信号处理
【嵌牛鼻子】linux C语言 信号
【嵌牛提问】linux下的C语言开发中如何进行信号处理?
信号处理是linux程序的一个特色。用信号处理来模拟操作系统的中断功能,对于我们这些系统程序员来说是最好的一个选择了。要想使用信号处理功能,你要做的就是填写一个信号处理函数即可。一旦进程有待处理的信号处理,那么进程就会立即进行处理。
#include stdio.h
#include stdlib.h
#include signal.h
int value = 0;
void func(int sig)
{
printf(“I get a signal!\n”);
value = 1;
}
int main()
{
signal(SIGINT, func);
while(0 == value)
sleep(1);
return 0;
}
为了显示linux对signal的处理流程,我们需要进行两个步骤。第一,输入gcc sig.c -o sig, 然后输入./sig即可;第二则重启一个console窗口,输入ps -aux | grep sig, 在获取sig的pid之后然后输入kill -INT 2082, 我们即可得到如下的输出。
[root@www.easyaq.com fork]#./sig
I get a signal!
[root@www.easyaq.com fork]#
请教一个Linux下C语言的进程间的信号问题
linux中的进程通信分为三个部分:低级通信,管道通信和进程间通信IPC(inter process communication)。linux的低级通信主要用来传递进程的控制信号——文件锁和软中断信号机制。linux的进程间通信IPC有三个部分——①信号量,②共享内存和③消息队列。以下是我编写的linux进程通信的C语言实现代码。操作系统为redhat9.0,编辑器为vi,编译器采用gcc。下面所有实现代码均已经通过测试,运行无误。
一.低级通信–信号通信
signal.c
#include
#include
#include
/*捕捉到信号sig之后,执行预先预定的动作函数*/
void sig_alarm(int sig)
{
printf(“—the signal received is %d. /n”, sig);
signal(SIGINT, SIG_DFL); //SIGINT终端中断信号,SIG_DFL:恢复默认行为,SIN_IGN:忽略信号
}
int main()
{
signal(SIGINT, sig_alarm);//捕捉终端中断信号
while(1)
{
printf(“waiting here!/n”);
sleep(1);
}
return 0;
}
二.管道通信
pipe.c
#include
#define BUFFER_SIZE 30
int main()
{
int x;
int fd[2];
char buf[BUFFER_SIZE];
char s[BUFFER_SIZE];
pipe(fd);//创建管道
while((x=fork())==-1);//创建管道失败时,进入循环
/*进入子进程,子进程向管道中写入一个字符串*/
if(x==0)
{
sprintf(buf,”This is an example of pipe!/n”);
write(fd[1],buf,BUFFER_SIZE);
exit(0);
}
/*进入父进程,父进程从管道的另一端读出刚才写入的字符串*/
else
{
wait(0);//等待子进程结束
read(fd[0],s,BUFFER_SIZE);//读出字符串,并将其储存在char s[]中
printf(“%s”,s);//打印字符串
}
return 0;
}
三.进程间通信——IPC
①信号量通信
sem.c
#include
#include
#include
#include types.h
#include ipc.h
#include sem.h
/*联合体变量*/
union semun
{
int val; //信号量初始值
struct semid_ds *buf;
unsigned short int *array;
struct seminfo *__buf;
};
/*函数声明,信号量定义*/
static int set_semvalue(void); //设置信号量
static void del_semvalue(void);//删除信号量
static int semaphore_p(void); //执行P操作
static int semaphore_v(void); //执行V操作
static int sem_id; //信号量标识符
int main(int argc, char *argv[])
{
int i;
int pause_time;
char op_char = ‘O’;
srand((unsigned int)getpid());
sem_id = semget((key_t)1234, 1, 0666 | IPC_CREAT);//创建一个信号量,IPC_CREAT表示创建一个新的信号量
/*如果有参数,设置信号量,修改字符*/
if (argc 1)
{
if (!set_semvalue())
{
fprintf(stderr, “Failed to initialize semaphore/n”);
exit(EXIT_FAILURE);
}
op_char = ‘X’;
sleep(5);
}
for(i = 0; i 10; i++)
{
/*执行P操作*/
if (!semaphore_p())
exit(EXIT_FAILURE);
printf(“%c”, op_char);
fflush(stdout);
pause_time = rand() % 3;
sleep(pause_time);
printf(“%c”, op_char);
fflush(stdout);
/*执行V操作*/
if (!semaphore_v())
exit(EXIT_FAILURE);
pause_time = rand() % 2;
sleep(pause_time);
}
printf(“/n%d – finished/n”, getpid());
if (argc 1)
{
sleep(10);
del_semvalue(); //删除信号量
}
exit(EXIT_SUCCESS);
}
/*设置信号量*/
static int set_semvalue(void)
{
union semun sem_union;
sem_union.val = 1;
if (semctl(sem_id, 0, SETVAL, sem_union) == -1)
return(0);
return(1);
}
/*删除信号量*/
static void del_semvalue(void)
{
union semun sem_union;
if (semctl(sem_id, 0, IPC_RMID, sem_union) == -1)
fprintf(stderr, “Failed to delete semaphore/n”);
}
/*执行P操作*/
static int semaphore_p(void)
{
struct sembuf sem_b;
sem_b.sem_num = 0;
sem_b.sem_op = -1; /* P() */
sem_b.sem_flg = SEM_UNDO;
if (semop(sem_id, sem_b, 1) == -1)
{
fprintf(stderr, “semaphore_p failed/n”);
return(0);
}
return(1);
}
/*执行V操作*/
static int semaphore_v(void)
{
struct sembuf sem_b;
sem_b.sem_num = 0;
sem_b.sem_op = 1; /* V() */
sem_b.sem_flg = SEM_UNDO;
if (semop(sem_id, sem_b, 1) == -1)
{
fprintf(stderr, “semaphore_v failed/n”);
return(0);
}
return(1);
}
②消息队列通信
send.c
#include
#include
#include
#include
#include
#include types.h
#include ipc.h
#include msg.h
#define MAX_TEXT 512
/*用于消息收发的结构体–my_msg_type:消息类型,some_text:消息正文*/
struct my_msg_st
{
long int my_msg_type;
char some_text[MAX_TEXT];
};
int main()
{
int running = 1;//程序运行标识符
struct my_msg_st some_data;
int msgid;//消息队列标识符
char buffer[BUFSIZ];
/*创建与接受者相同的消息队列*/
msgid = msgget((key_t)1234, 0666 | IPC_CREAT);
if (msgid == -1)
{
fprintf(stderr, “msgget failed with error: %d/n”, errno);
exit(EXIT_FAILURE);
}
/*向消息队列中发送消息*/
while(running)
{
printf(“Enter some text: “);
fgets(buffer, BUFSIZ, stdin);
some_data.my_msg_type = 1;
strcpy(some_data.some_text, buffer);
if (msgsnd(msgid, (void *)some_data, MAX_TEXT, 0) == -1)
{
fprintf(stderr, “msgsnd failed/n”);
exit(EXIT_FAILURE);
}
if (strncmp(buffer, “end”, 3) == 0)
{
running = 0;
}
}
exit(EXIT_SUCCESS);
}
receive.c
#include
#include
#include
#include
#include
#include types.h
#include ipc.h
#include msg.h
/*用于消息收发的结构体–my_msg_type:消息类型,some_text:消息正文*/
struct my_msg_st
{
long int my_msg_type;
char some_text[BUFSIZ];
};
int main()
{
int running = 1;//程序运行标识符
int msgid; //消息队列标识符
struct my_msg_st some_data;
long int msg_to_receive = 0;//接收消息的类型–0表示msgid队列上的第一个消息
/*创建消息队列*/
msgid = msgget((key_t)1234, 0666 | IPC_CREAT);
if (msgid == -1)
{
fprintf(stderr, “msgget failed with error: %d/n”, errno);
exit(EXIT_FAILURE);
}
/*接收消息*/
while(running)
{
if (msgrcv(msgid, (void *)some_data, BUFSIZ,msg_to_receive, 0) == -1)
{
fprintf(stderr, “msgrcv failed with error: %d/n”, errno);
exit(EXIT_FAILURE);
}
printf(“You wrote: %s”, some_data.some_text);
if (strncmp(some_data.some_text, “end”, 3) == 0)
{
running = 0;
}
}
/*删除消息队列*/
if (msgctl(msgid, IPC_RMID, 0) == -1)
{
fprintf(stderr, “msgctl(IPC_RMID) failed/n”);
exit(EXIT_FAILURE);
}
exit(EXIT_SUCCESS);
}
③共享内存通信
share.h
#define TEXT_SZ 2048 //申请共享内存大小
struct shared_use_st
{
int written_by_you; //written_by_you为1时表示有数据写入,为0时表示数据已经被消费者提走
char some_text[TEXT_SZ];
};
producer.c
#include
#include
#include
#include
#include types.h
#include ipc.h
#include shm.h
#include “share.h”
int main()
{
int running = 1; //程序运行标志位
void *shared_memory = (void *)0;
struct shared_use_st *shared_stuff;
char buffer[BUFSIZ];
int shmid; //共享内存标识符
/*创建共享内存*/
shmid = shmget((key_t)1234, sizeof(struct shared_use_st), 0666 | IPC_CREAT);
if (shmid == -1)
{
fprintf(stderr, “shmget failed/n”);
exit(EXIT_FAILURE);
}
/*将共享内存连接到一个进程的地址空间中*/
shared_memory = shmat(shmid, (void *)0, 0);//指向共享内存第一个字节的指针
if (shared_memory == (void *)-1)
{
fprintf(stderr, “shmat failed/n”);
exit(EXIT_FAILURE);
}
printf(“Memory attached at %X/n”, (int)shared_memory);
shared_stuff = (struct shared_use_st *)shared_memory;
/*生产者写入数据*/
while(running)
{
while(shared_stuff-written_by_you == 1)
{
sleep(1);
printf(“waiting for client…/n”);
}
printf(“Enter some text: “);
fgets(buffer, BUFSIZ, stdin);
strncpy(shared_stuff-some_text, buffer, TEXT_SZ);
shared_stuff-written_by_you = 1;
if (strncmp(buffer, “end”, 3) == 0)
{
running = 0;
}
}
/*该函数用来将共享内存从当前进程中分离,仅使得当前进程不再能使用该共享内存*/
if (shmdt(shared_memory) == -1)
{
fprintf(stderr, “shmdt failed/n”);
exit(EXIT_FAILURE);
}
printf(“producer exit./n”);
exit(EXIT_SUCCESS);
}
customer.c
#include
#include
#include
#include
#include types.h
#include ipc.h
#include shm.h
#include “share.h”
int main()
{
int running = 1;//程序运行标志位
void *shared_memory = (void *)0;
struct shared_use_st *shared_stuff;
int shmid; //共享内存标识符
srand((unsigned int)getpid());
/*创建共享内存*/
shmid = shmget((key_t)1234, sizeof(struct shared_use_st), 0666 | IPC_CREAT);
if (shmid == -1)
{
fprintf(stderr, “shmget failed/n”);
exit(EXIT_FAILURE);
}
/*将共享内存连接到一个进程的地址空间中*/
shared_memory = shmat(shmid, (void *)0, 0);//指向共享内存第一个字节的指针
if (shared_memory == (void *)-1)
{
fprintf(stderr, “shmat failed/n”);
exit(EXIT_FAILURE);
}
printf(“Memory attached at %X/n”, (int)shared_memory);
shared_stuff = (struct shared_use_st *)shared_memory;
shared_stuff-written_by_you = 0;
/*消费者读取数据*/
while(running)
{
if (shared_stuff-written_by_you)
{
printf(“You wrote: %s”, shared_stuff-some_text);
sleep( rand() % 4 );
shared_stuff-written_by_you = 0;
if (strncmp(shared_stuff-some_text, “end”, 3) == 0)
{
running = 0;
}
}
}
/*该函数用来将共享内存从当前进程中分离,仅使得当前进程不再能使用该共享内存*/
if (shmdt(shared_memory) == -1)
{
fprintf(stderr, “shmdt failed/n”);
exit(EXIT_FAILURE);
}
/*将共享内存删除,所有进程均不能再访问该共享内存*/
if (shmctl(shmid, IPC_RMID, 0) == -1)
{
fprintf(stderr, “shmctl(IPC_RMID) failed/n”);
exit(EXIT_FAILURE);
}
exit(EXIT_SUCCESS);
}
摘自:
linux中c语言有关信号的程序
简单处理了一下,希望对你有帮助
#define err_sys( str ) printf(“error:%s\n” , str )
static void sig_int(int signo)
{
struct tms timebuf;
int wallclock=times(timebuf);
fprintf(stderr,”clock ticks since system startup are %d,\n”,wallclock);
}
static void sig_term(int signo)
{
struct tms timebuf;
int wallclock=times(timebuf);
fprintf(stderr,”clock ticks since system start are %d,\n”,wallclock);
exit(0); //终止程序
}
static void sig_alrm(int signo)
{
static int times=1;
alarm(0);//输出时,不再计时
printf(“time:%d\n” , times*10 );
times++ ;
alarm(10); //重新开始计时
}
int main()
{
if (signal(SIGINT,sig_int)==SIG_ERR)
err_sys(“can’t catch SIGINT”);
if (signal(SIGTERM,sig_term)==SIG_ERR)
err_sys(“can’t catch SIGTERM”);
alarm(10); //开始计时
if (signal(SIGALRM,sig_alrm)==SIG_ERR)
err_sys(“can’t catch SIGALRM”);
while(1) ; //等待在这里
return(0);
}
如何用C语言实现数字信号处理算法?
下面的资料可看一下
C语言实现数字信号处理算法
数字信号处理C语言程序集》
scilab,octave是C语言实现的开源的类matlab软件,里面有许多c语言实现的数字信号处理的算法,可以研究一下。
c语言设计 射频信号相位分析
30MHz信号f(t)=A*cos(2*3.1415927*f*t),令f=30M,t=nT,其中T为采样周期,就是模拟采样。
如果要加相位抖动参数,就是cos(2*3.1415927*f*t+g(t)),g(t)是抖动信号。
谐波频率参数就是把几个不同频率cos信号相加。