dmesg | grep DDR

spdmem0 at iic0 addr 0x50: 2GB DDR3 SDRAM PC3-10600
spdmem1 at iic0 addr 0x52: 2GB DDR3 SDRAM PC3-10600

#include <stdio.h>
#include <errno.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/select.h>
#include <fcntl.h>
#include <string.h>
#include <unistd.h>
#include <pthread.h>

#define DimensionOf(rg) (sizeof(rg) / sizeof(rg[0]))

void* handleio(void* state)
{
  printf("handleio thread starting\n");
  int fds[128];
  
  for (int i = 0; i < DimensionOf(fds); ++i)
    {
    fds[i] = -1;
    }
  
  // Open the pipe instances.

  fd_set rfds;
  FD_ZERO(&rfds);
  for (int i = 0; i < DimensionOf(fds); ++i)
    {
      fds[i] = open((char*) state, O_RDONLY | O_NONBLOCK);
    if (fds[i] == -1)
      {
	printf("Failed opening pipe s, errno = %d\n", (char*) state, errno);
      goto done;
      }
    FD_SET(fds[i], &rfds);
    }

  while (1)
    {
      int ready = select(fds[DimensionOf(fds) - 1] + 1, &rfds, NULL,
	     NULL, NULL);
      if (ready == -1)
	{
	  printf("select() failed, error = %d\n", errno);
	  goto done;
	}
      printf("select return %d\n", ready);
      for (int i = 0; i < DimensionOf(fds); ++i)
	{
	if (FD_ISSET(fds[i], &rfds) != 0)
	  {
	  printf("fd %d is set", fds[i]);
	  }
	}
      break;
    }
done:
  printf("handleio thread returning\n");
}

void main(int argc, char* argv[])
{
  if (argc != 2)
    {
    printf("Expecting fifo path.\n");
    goto done;
    }

  // Block SIGINT.
  
  sigset_t sigset;
  sigemptyset(&sigset);
  sigaddset(&sigset, SIGINT);
  if (pthread_sigmask(SIG_BLOCK, &sigset, NULL) != 0)
    {
    printf("Failed setting sigmask\n");
    goto done;
    }

  // Start the thread which will handle the IO on the pipe instances.
  
  pthread_t iothread;
  if (pthread_create(&iothread, NULL, handleio, argv[1]) != 0)
    {
    printf("Failed creating IO thread, errno = %d\n", errno);
    goto done;
    }
  
  sigemptyset(&sigset);
  sigaddset(&sigset, SIGINT);
  int sig;
  int result = sigwait(&sigset, &sig);
  if (result == 0)
    printf("sigwait got signal: %d\n", sig);

done:
  ;
}

#include "stdio.h"
#include "errno.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>

void main(int argc, char* argv[])
{
  int fd;

  if (argc != 2)
    printf("Expecting fifo path.\n");
  else
    {
    fd = open(argv[1], O_WRONLY | O_NONBLOCK | O_ASYNC);
    if (fd == -1)
        {
	printf("Failed opening pipe %s, errno = %d\n", argv[1], errno);
	}
    else
	{
	char message[] = "This is a test";
	printf("Successfully opened pipe, fd = %d\n", fd);
	int count = sizeof(message) / sizeof(message[0]);
	int total = 0;
	while (total != count)
	  {
	    int written = write(fd, &message[total], count - total);
	    if (written == -1)
	      {
		printf("Failed writing to pipe, errno = %d\n", errno);
		break;
	      }
	    total += written;
	  }
	close(fd);
	}
    }
}