Sample daemonizing code in C

alvd.c

#include <stdarg.h> 
#include <stdio.h> 
#include <string.h> 
#include <signal.h> 
#include <stdlib.h> 
#include <sys/types.h> 

void bye(int sig);

int main( int argc, char *argv[] )
{
  memset(argv[0], 0, strlen(argv[0])); // clears daemon name & arguments
  strcpy(argv[0], "alvarowd"); // makes pretty/short on process table

  // Forks to background 
  pid_t pid;
  pid = fork();

  if (pid < 0) {
	perror("fork");
        exit(1); // error encountered, no child has been created! 
  }

  if (pid != 0) { // this is the parent, hence should exit 
	printf("Parent %d: I quit!\n", getpid());
        exit(0); 
  }

  /* this is the child process of the child process of the actual calling process 
     and can safely be called a grandchild of the original process */

  setsid(); // make the process a group leader, session leader, and lose control tty 
//  umask(0); /* lose file creation mode mask inherited by parent */
  chdir("/"); /* change working dir, so we can umount */

  // close STDOUT, STDIN, STDERR 
/*
  close(STDIN_FILENO);
  close(STDOUT_FILENO);
  close(STDERR_FILENO);
*/
//  Fecha todos os descritores abertos pelo processo.
//  int i;
//  for (i=getdtablesize();i>=0;--i) close(i);
//  i=open("/dev/null",O_RDWR); dup(i); dup(i);

  signal(SIGTERM, bye); // Sends a message when going away
  signal(SIGHUP, SIG_IGN); // ignore SIGHUP that will be sent to a child of the process 
  signal(SIGPIPE, SIG_IGN); // ignore SIGPIPE, for reading, writing to non-opened pipes 
  // every program using pipes should ignore this signal for being on the safe side 

 //daemon();
  printf("Child %d: Here I go!\n", getpid());
  printf("Child %d: looping forever... see you on eternity!\n", getpid());
  int i; for(i=0;i==0;i++) {
     i--;
     sleep(1);
  };

return 0; // never gets here
} // end of main 


/* handler when program is terminated normally */
void bye(int signal)
{
   printf("CHILD %d: I have received a SIGTERM\n", getpid());
   printf("CHILD %d: Now I die. Good bye.\n", getpid());
   exit(0); 
   //_exit(0); // Child should exit with _exit?
}