Question

我想通过子进程中的结构将测量数据发送到Parent。父进程必须打印10个测量数据的平均值。

funcs.h中的结构数据：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data;
using System.ComponentModel;

namespace ConvertListToDataTable
{
    public static class Program
    {
        public static void Main(string[] args)
        {
            List<MyObject> list = new List<MyObject>();
            for (int i = 0; i < 5; i++)
            {
                list.Add(new MyObject { Sno = i, Name = i.ToString() + "-KarthiK", Dat = DateTime.Now.AddSeconds(i) });
            }

            DataTable dt = ConvertListToDataTable(list);
            foreach (DataRow row in dt.Rows)
            {
                Console.WriteLine();
                for (int x = 0; x < dt.Columns.Count; x++)
                {
                    Console.Write(row[x].ToString() + " ");
                }
            }
            Console.ReadLine();
        }

        public class MyObject
        {
            public int Sno { get; set; }
            public string Name { get; set; }
            public DateTime Dat { get; set; }
        }

        public static DataTable ConvertListToDataTable<T>(this List<T> iList)
        {
            DataTable dataTable = new DataTable();
            PropertyDescriptorCollection props = TypeDescriptor.GetProperties(typeof(T));
            for (int i = 0; i < props.Count; i++)
            {
                PropertyDescriptor propertyDescriptor = props[i];
                Type type = propertyDescriptor.PropertyType;

                if (type.IsGenericType && type.GetGenericTypeDefinition() == typeof(Nullable<>))
                    type = Nullable.GetUnderlyingType(type);

                dataTable.Columns.Add(propertyDescriptor.Name, type);
            }
            object[] values = new object[props.Count];
            foreach (T iListItem in iList)
            {
                for (int i = 0; i < values.Length; i++)
                {
                    values[i] = props[i].GetValue(iListItem);
                }
                dataTable.Rows.Add(values);
            }
            return dataTable;
        }
    }
}

uebung2_1.c（主要）：

struct data{
int nr;
float temp;
float bst;
float abst;
};

子进程通过linux中断每500ns发送一次测量数据。我首先使用char数组测试它并且它成功了。

sohn.c：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <math.h>
#include <time.h>
#include <signal.h>
#include <stdio.h>
#include "funcs.h"

#define READ_END 0
#define WRITE_END 1
#define CHILD "./sohn"

int main(){
    int w_status, pid_fork, i, k;
    double midT, midB, midA;
    int pfd[2];
    struct data buf;

    if(pipe(pfd) == -1){
        perror("ERROR creating a pipe\n");
        exit(EXIT_FAILURE);
    }

    pid_fork = fork();
    switch(pid_fork){
        case(-1):
            perror("fork()");
            return EXIT_FAILURE;
        case(0):
            dup2(pfd[WRITE_END], STDOUT_FILENO);
            close(pfd[READ_END]);
            execlp(CHILD,CHILD,NULL);
            perror("exec is failed");
            break;
        default:
            close(pfd[WRITE_END]);
            printf("Sohn gestartet mit PID %d\n", pid_fork);
            midT = midB = midA = 0;
            i = k = 0;
            while(1){
                read(pfd[READ_END],&buf,sizeof(struct data));
                midT += buf.temp;
                midB += buf.bst;
                midA += buf.abst;
                i++;
                if(i == 10){
                    midT /=10;
                    midB /=10;
                    midA /=10;
                    printf("Messung. %4i: Temp.: %4.1lf, Beleucht.: %4lf, Abstand: %3.1lf\n",k++, midT, midB, midA);
                    midT = midB = midA = 0;
                    i = 0;
                }
            }
            while(i != -1){
                i = wait(&w_status);
                if(i != -1)
                    printf("\nSohn beendet. Exit Status: %x Nummer des Sohn-Prozesses %d",
                        (w_status>>8) & 0xff, i);
                    else
                        printf("\nLetzter Sohn beendet!\n");
            }
        }
    return 0;
}

输出：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <math.h>
#include <time.h>
#include <signal.h>
#include <stdio.h>
#include <sys/time.h>
#include "funcs.h"

#define INTERVAL 500000

int howmany = 0;

void alarm_wakeup (int i)
{
    struct itimerval tout_val;
    howmany += INTERVAL;
    tout_val.it_interval.tv_sec = 0;
    tout_val.it_interval.tv_usec = 0;
    tout_val.it_value.tv_sec = 0;
    tout_val.it_value.tv_usec = INTERVAL;
    setitimer(ITIMER_REAL, &tout_val,0);
}

void exit_func (int i)
{
    signal(SIGINT,exit_func);
    exit(0);
}



int main(){

    struct data mess;
    struct itimerval tout_val;
    tout_val.it_interval.tv_sec = 0;
    tout_val.it_interval.tv_usec = 0;
    tout_val.it_value.tv_sec = 0;
    tout_val.it_value.tv_usec = INTERVAL;
    setitimer(ITIMER_REAL, &tout_val,0);
    signal(SIGALRM,alarm_wakeup);
    signal(SIGINT,exit_func);

    srand(time(0));
    mess.nr = 0;
    while (1) {
        mess.nr++;
        mess.temp = (rand()%1001)/10 - 20;
        mess.bst = rand()%1000 + 1;
        mess.abst = rand()%26 + 4;
        write(STDIN_FILENO,&mess, sizeof(struct data));
        sleep(10);
    }

    exit(0);
}

使用strace输出：

Sohn gestartet mit PID 3488
�BhB�A@��@�A�B�!DA@ATCpA�B@D A4B�C�A0A@#D0dB�sDA        4B��CpA
��\D�A^C

我用ctrl + c杀了进程。为什么是象形文字？

-------------------------------------------- -------------------------------

更新我在孩子（sohn.c）写的标准输入，但它对输出很好。感谢Joachim Pileborg

Answer 1

我在孩子（sohn.c）中写到标准输入，但它对输出很感兴趣。感谢Joachim Pileborg

- Raze

pipe（）将struct从child发送到parent。 read（）中的象形文字;

1 个答案: