Следующий сервер создает именованный канал при его запуске следующим образом:
./serverprogram -p nameofthepipe -t 99
optarg после t указывает количество создаваемых потоков (здесь не сделано).
В любом случае, труба здесь не работает:
/* Open the first named pipe for reading */
int rdfd = open(pipeName, O_RDONLY);
/* Read from the first pipe */
int numread = read(rdfd, command_and_pid, 280);
printf("what's being read is %s \n", command_and_pid); // not printing!!1!
Почему?
Серверная программа:
#include <unistd.h>
#include <stdio.h>
#include <errno.h>
#include <ctype.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <string.h>
#include <stdlib.h>
#include <string.h>
#include <pthread.h>
int main (int argc, char * argv[])
{
char pipeName[30];
int numThreads;
char command_and_pid[280];
int opcion;
if (argc < 2) {
printf ("ERROR: Missing arguments\n");//
exit(1);
}
opterr = 0;
while ((opcion = getopt (argc, argv, "p:t:w")) != -1)
{
switch (opcion) {
case 'p': // -p indica el nombre del pipe
printf("The name of the pipe is: %s\n",optarg);
strcpy(pipeName, optarg);
break;
case 't'://-t indica los hilos
printf("The number of threads is: %s\n",optarg);
numThreads= atoi(optarg);
break;
case '?':
fprintf(stderr,"no reconozco esa opcion\n");
break;
}
}
int ret_val = mkfifo(pipeName, 0666);
if ((ret_val == -1) && (errno != EEXIST)) {
perror("Error creating the named pipe");
exit (0);
}
/* Open the first named pipe for reading */
int rdfd = open(pipeName, O_RDONLY);
/* Read from the first pipe */
int numread = read(rdfd, command_and_pid, 280);
printf("what's being read is %s \n", command_and_pid); // not printing!!1!
close(rdfd);
return 0;
}
Клиентская программа:
#include <unistd.h>
#include<stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <pthread.h>
int main (int argc, char * argv[])
{
char pipeName[30];
printf("write the name of the pipe used to write to the server \n");
fgets(pipeName,30, stdin);
/* Open the first named pipe for writing */
int wrfd = open(pipeName, O_WRONLY);
printf("write the name of the command you want to execute \n");
char command_and_pid[280];
char command[250];
fgets(command,250, stdin);
puts(command); //quitar
strcpy(command_and_pid,command);
strcat(command_and_pid," ");
int pipeIntId;
char pidstring [30];
int pid= getpid();
sprintf(pidstring,"%d", pid);
strcat(command_and_pid,pidstring);
int written;
written=write(pipeIntId,command_and_pid,280);
//write to the pipe
// send the command and pid
close(pipeIntId); // close write pipe
return 0;
}