Unix Inotify in C

watcher.c

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/types.h>
#include <linux/inotify.h>

#define EVENT_SIZE  ( sizeof (struct inotify_event) )
#define EVENT_BUF_LEN     ( 1024 * ( EVENT_SIZE + 16 ) )

int main( )
{
  int length, i = 0;
  int fd;
  int wd;
  char buffer[EVENT_BUF_LEN];
  char  *p;
  struct inotify_event *event;

  fd = inotify_init();
  if ( fd < 0 ) {
	printf("inotify_init failed");
	exit(EXIT_FAILURE);
  }
	

  wd = inotify_add_watch( fd, "/home/user/src/package.json", IN_MODIFY | IN_OPEN );
  if ( wd < 0) {
	printf("inotify_add_watch failed");
	exit(EXIT_FAILURE);
  }

  printf("Using wd %d\n", wd);

  for (;;) {
	  length = read( fd, buffer, EVENT_BUF_LEN ); 
	  if ( length < 0 ) {
	    printf("Something went wrong during read()");
	    perror( "read" );
	  }  
	  for (p = buffer; p < buffer + length; ){
	      event = (struct inotify_event *) p;
	      if ( event->mask & IN_MODIFY ) {
		 /*system( "npm install" );*/
		 system("echo 'HelloWorld'");
	      } 
	      p += EVENT_SIZE + event->len;
	  }
  }
   inotify_rm_watch( fd, wd );
   close( fd );
}