Linux API/linux2022. 10. 26. 14:24

가능은 한 것 같은데..

[링크 : https://stackoverflow.com/questions/15055065/o-rdwr-on-named-pipes-with-poll]

[링크 : https://man7.org/linux/man-pages/man3/mkfifo.3.html]

 

Macro: int ENXIO“No such device or address.” The system tried to use the device represented by a file you specified, and it couldn’t find the device. This can mean that the device file was installed incorrectly, or that the physical device is missing or not correctly attached to the computer.

[링크 : https://www.gnu.org/software/libc/manual/html_node/Error-Codes.html]

 

+

2022.10.27

POLLIN으로 탐지가 되는 듯?

$ cat rx.c
//#define _GNU_SOURCE

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <linux/fcntl.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <errno.h>
#include <sys/poll.h>

#define  FIFO_FILE   "/tmp/fifo"
#define  BUFF_SIZE  1024*768*4
struct pollfd pfd[1];

int main(int argc, char** argv)
{
                int ret = 0;
                int   counter = 0;
                int   fd;
                char  buff[BUFF_SIZE];

                //              printf("argc[%d]\n",argc);
                if ( -1 == mkfifo( FIFO_FILE, 0666)){
                                perror( "mkfifo() 실행에러");
                                exit( 1);
                }

                if ( -1 == ( fd = open( FIFO_FILE, O_RDONLY|O_NONBLOCK))){  //  <---- (A)
                                perror( "open() 실행에러");
                                exit( 1);
                }
                ret = fcntl(fd, F_SETPIPE_SZ, 1024 * 1024);
                pfd[0].fd = fd;
                pfd[0].events = POLLIN;

                printf("fd[%d]ret[%d]\n",fd,ret);

                while( 1 ){
                                int n = poll(pfd, 1, 10);
                                if (n > 0)
                                {
                                        memset( buff, 0, BUFF_SIZE);
                                        ret = read( fd, buff, BUFF_SIZE);
                                        if(ret > 0 )
                                                        printf("ret[%d]\n",ret);
                                        //      printf( "%d: %s\n", counter++, buff);
                                }
                                printf(".");
                                usleep(10000);
                }
                close( fd);
}
$ cat tx.c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <signal.h>

#define  FIFO_FILE   "/tmp/fifo"

int main_loop = 1;
int write_loop = 1;

void sigint_handler(int sig)
{
                main_loop = 0;
                write_loop = 0;
}

void sigpipe_handler(int sig)
{
                write_loop = 0;
}

int main(int argc, char **argv)
{
                int   fd;
                int   fd_r;
                //   char *str   = "badayak.com";
                char *str = NULL;
                char *temp = NULL;

                str = (char*)malloc(1024*768*4);
                temp = (char*)malloc(1024*768*4);
                memset(str, *argv[1], 1024*768*4);

//              signal(SIGPIPE, SIG_IGN);
                signal(SIGPIPE, &sigpipe_handler);
                signal(SIGINT, &sigint_handler);
                /*
                   printf("%d\n",__LINE__);
                   if ( -1 == mkfifo( FIFO_FILE, 0666)){
                   perror( "mkfifo() 실행에러");
                   exit( 1);
                   }
                 */
                while(main_loop)
                {
                                printf("%d\n",__LINE__);
                                do {
                                                fd = open( FIFO_FILE, O_WRONLY | O_NONBLOCK);
                                                usleep(100000);
                                                printf("fd[%d] %d\n",fd,__LINE__);
                                                if(main_loop == 0 && write_loop == 0) exit(1);
                                } while(fd == -1);
                                write_loop = 1;

                                int ret = 0;
                                while(write_loop)
                                {
                                                printf("%d\n",__LINE__);
                                                int a = write( fd, str, atoi(argv[1]));
                                                printf("%d a[%d]\n",__LINE__,a);
                                                usleep(1000000);
                                }
                }
                close( fd);
}

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