标签:int 简单 bytes PPS state fd 使用 include buf
//subscriber/main.cpp
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
int main(int argc, char *argv[])
{
int fd;
char buf[256];
int num_bytes;
fd = open( "/pps/button?wait,delta", O_RDONLY );
if ( fd < 0 )
{
perror ("Couldn't open /pps/button");
return EXIT_FAILURE;
}
/* Loop, echoing the attributes of the button. */
while (1)
{
num_bytes = read( fd, buf, sizeof(buf) );
if (num_bytes > 0)
{
write (STDOUT_FILENO, buf, num_bytes);
}
}
return EXIT_SUCCESS;
}
//publish/main.cpp
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <errno.h>
int main(int argc, char *argv[])
{
int fd;
int state = 0;
char buf[256];
struct stat stat_buf;
int count = 0;
ssize_t len, bytes_written;
/* Is PPS running? */
if (stat( "/pps", &stat_buf) != 0)
{
if (errno == ENOENT)
printf ("The PPS server isn't running.\n");
else
perror ("stat (/pps)");
return EXIT_FAILURE;
}
/* Create the "button" object (if it doesn't already exist). */
fd = open( "/pps/button", O_RDWR | O_CREAT, S_IRWXU | S_IRWXG | S_IRWXO );
if ( fd < 0 )
{
perror ("Couldn't open /pps/button");
return EXIT_FAILURE;
}
/* Loop forever, toggling the state of the button. */
while ( 1 )
{
usleep (500);
count++;
len = snprintf(buf, 256, "state::%s\npub1::%d", state ? "on" : "off", count);
bytes_written = write( fd, buf, len );
if (bytes_written == -1)
{
perror ("write()");
}
else if (bytes_written != len)
{
printf ("Bytes written: %d String length: %d\n", bytes_written, len);
}
if ( state == 0 )
state = 1;
else
state = 0;
}
return EXIT_SUCCESS;
}
标签:int,简单,bytes,PPS,state,fd,使用,include,buf 来源: https://blog.csdn.net/m0_37844072/article/details/121996347
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