- Added some more comment to OS ass3.

os/ass3/fishbones.c

@@ -6,6 +6,9 @@
 #include <errno.h>
 #include <signal.h>
 
+/*
+ * Read from pipe (child processes only).
+ */
 static void gup(FILE * log1, FILE * log2, int pipe_id[2], int myNumber)
 {
 	FILE * log3;
@@ -94,6 +97,9 @@ static void gup(FILE * log1, FILE * log2, int pipe_id[2], int myNumber)
 	exit(0);
 }
 
+/*
+ * Signal handler for SIGINT, SIGTERM and SIGCHLD.
+ */
 void
 signal_handler(int signum)
 {
@@ -111,6 +117,9 @@ signal_handler(int signum)
     }
 }
 
+/*
+ * Main funtion, initiates the program.
+ */
 int
 main(int argc, char * argv[])
 {
@@ -125,18 +134,17 @@ main(int argc, char * argv[])
 	log2 = fopen("child.log2", "wt+");
 	setvbuf(log2, NULL, _IONBF, BUFSIZ);
 	/* So log1 is buffered; log2 is not buffered, which means that output
-	   to log2 is written immediately. */
+	 * to log2 is written immediately. */
 	
-	/* create the pipe somewhere around here (why?).
-	   remember to test for success!! */
-	
-	if( pipe(pipe_id) )
+	/* Create pipe, exit with error on failure */
+    if( pipe(pipe_id) )
 	{
 		fprintf(stderr, "Error %d occured while creating the pipe \n",
                 errno);
 		exit(1);
 	}	
-
+    
+    /* Bind signal handlers */
     action.sa_handler = signal_handler;
 
     if( sigaction(SIGINT, &action, NULL) < 0
@@ -147,15 +155,9 @@ main(int argc, char * argv[])
         exit(1);
     }
     
+    /* Keep reading input */
 	while( (c = getchar()) )
 	{
-		/* You can now choose to use only the first character in the
-		   string (inString[0]), or the entire string (how would you test
-		   that?).
-		   Anyway, read a character, echo it to both log files 
-		   and write it into the pipe (unless you have to call fork)
-		   */
-		
 		/* Ignore newlines and spaces */
 		if( c == '\n' || c == 32 )
 		{
@@ -180,7 +182,7 @@ main(int argc, char * argv[])
 				exit(1);
 			}
                
-            /* Wait for child process to 'eat poison' */
+            /* Wait for child process to 'eat the poison' */
 			if( c == 'P' )
                 wait(NULL);
 		}