Initial revision

16 files changed, 649 insertions, 0 deletions

diff --git a/manual/examples/add.c b/manual/examples/add.c
new file mode 100644
index 0000000000..cb37b2b435
--- /dev/null
+++ b/manual/examples/add.c
@@ -0,0 +1,30 @@
+#include <stdarg.h>
+#include <stdio.h>
+
+int
+add_em_up (int count,...)
+{
+  va_list ap;
+  int i, sum;
+
+  va_start (ap, count);		/* Initialize the argument list. */
+
+  sum = 0;
+  for (i = 0; i < count; i++)
+    sum = sum + va_arg (ap, int);	/* Get the next argument value. */
+
+  va_end (ap);			/* Clean up. */
+  return sum;
+}
+
+int
+main (void)
+{
+  /* This call prints 16. */
+  printf ("%d\n", add_em_up (3, 5, 5, 6));
+
+  /* This call prints 55. */
+  printf ("%d\n", add_em_up (10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10));
+
+  return 0;
+}
diff --git a/manual/examples/db.c b/manual/examples/db.c
new file mode 100644
index 0000000000..a8403ddd59
--- /dev/null
+++ b/manual/examples/db.c
@@ -0,0 +1,50 @@
+#include <grp.h>
+#include <pwd.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <stdlib.h>
+
+void 
+main (void)
+{
+  uid_t me;
+  struct passwd *my_passwd;
+  struct group *my_group;
+  char **members;
+
+  /* Get information about the user ID. */
+  me = getuid ();
+  my_passwd = getpwuid (me);
+  if (!my_passwd)
+    {
+      printf ("Couldn't find out about user %d.\n", (int) me);
+      exit (EXIT_FAILURE);
+    }
+
+  /* Print the information. */
+  printf ("My login name is %s.\n", my_passwd->pw_name);
+  printf ("My uid is %d.\n", (int) (my_passwd->pw_uid));
+  printf ("My home directory is %s.\n", my_passwd->pw_dir);
+  printf ("My default shell is %s.\n", my_passwd->pw_shell);
+
+  /* Get information about the default group ID. */
+  my_group = getgrgid (my_passwd->pw_gid);
+  if (!my_group)
+    {
+      printf ("Couldn't find out about group %d.\n", (int) (my_passwd->pw_gid));
+      exit (EXIT_FAILURE);
+    }
+
+  /* Print the information. */
+  printf ("My default group is %s (%d).\n",
+	  my_group->gr_name, (int) (my_passwd->pw_gid));
+  printf ("The members of this group are:\n");
+  members = my_group->gr_mem;
+  while (*members)
+    {
+      printf ("  %s\n", *(members));
+      members++;
+    }
+
+  exit (EXIT_SUCCESS);
+}
diff --git a/manual/examples/dir.c b/manual/examples/dir.c
new file mode 100644
index 0000000000..05aa5422cb
--- /dev/null
+++ b/manual/examples/dir.c
@@ -0,0 +1,23 @@
+#include <stddef.h>
+#include <stdio.h>
+#include <sys/types.h>
+#include <dirent.h>
+
+int
+main (void)
+{
+  DIR *dp;
+  struct dirent *ep;
+
+  dp = opendir ("./");
+  if (dp != NULL)
+    {
+      while (ep = readdir (dp))
+	puts (ep->d_name);
+      (void) closedir (dp);
+    }
+  else
+    puts ("Couldn't open the directory.");
+
+  return 0;
+}
diff --git a/manual/examples/memopen.c b/manual/examples/memopen.c
new file mode 100644
index 0000000000..682830fe5f
--- /dev/null
+++ b/manual/examples/memopen.c
@@ -0,0 +1,17 @@
+#include <stdio.h>
+
+static char buffer[] = "foobar";
+
+int
+main (void)
+{
+  int ch;
+  FILE *stream;
+
+  stream = fmemopen (buffer, strlen (buffer), "r");
+  while ((ch = fgetc (stream)) != EOF)
+    printf ("Got %c\n", ch);
+  fclose (stream);
+
+  return 0;
+}
diff --git a/manual/examples/memstrm.c b/manual/examples/memstrm.c
new file mode 100644
index 0000000000..7119f70d2d
--- /dev/null
+++ b/manual/examples/memstrm.c
@@ -0,0 +1,19 @@
+#include <stdio.h>
+
+int
+main (void)
+{
+  char *bp;
+  size_t size;
+  FILE *stream;
+
+  stream = open_memstream (&bp, &size);
+  fprintf (stream, "hello");
+  fflush (stream);
+  printf ("buf = %s, size = %d\n", bp, size);
+  fprintf (stream, ", world");
+  fclose (stream);
+  printf ("buf = %s, size = %d\n", bp, size);
+
+  return 0;
+}
diff --git a/manual/examples/pipe.c b/manual/examples/pipe.c
new file mode 100644
index 0000000000..c0e242ee20
--- /dev/null
+++ b/manual/examples/pipe.c
@@ -0,0 +1,64 @@
+#include <sys/types.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+/* Read characters from the pipe and echo them to stdout.  */
+
+void 
+read_from_pipe (int file)
+{
+  FILE *stream;
+  int c;
+  stream = fdopen (file, "r");
+  while ((c = fgetc (stream)) != EOF)
+    putchar (c);
+  fclose (stream);
+}
+
+/* Write some random text to the pipe. */
+
+void 
+write_to_pipe (int file)
+{
+  FILE *stream;
+  stream = fdopen (file, "w");
+  fprintf (stream, "hello, world!\n");
+  fprintf (stream, "goodbye, world!\n");
+  fclose (stream);
+}
+
+int
+main (void)
+{
+  pid_t pid;
+  int mypipe[2];
+
+  /* Create the pipe. */
+  if (pipe (mypipe))
+    {
+      fprintf (stderr, "Pipe failed.\n");
+      return EXIT_FAILURE;
+    }
+
+  /* Create the child process. */
+  pid = fork ();
+  if (pid == (pid_t) 0)
+    {
+      /* This is the child process. */
+      read_from_pipe (mypipe[0]);
+      return EXIT_SUCCESS;
+    }
+  else if (pid < (pid_t) 0)
+    {
+      /* The fork failed. */
+      fprintf (stderr, "Fork failed.\n");
+      return EXIT_FAILURE;
+    }
+  else
+    {
+      /* This is the parent process. */
+      write_to_pipe (mypipe[1]);
+      return EXIT_SUCCESS;
+    }
+}
diff --git a/manual/examples/popen.c b/manual/examples/popen.c
new file mode 100644
index 0000000000..15a085e2cc
--- /dev/null
+++ b/manual/examples/popen.c
@@ -0,0 +1,31 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+void 
+write_data (FILE * stream)
+{
+  int i;
+  for (i = 0; i < 100; i++)
+    fprintf (stream, "%d\n", i);
+  if (ferror (stream))
+    {
+      fprintf (stderr, "Output to stream failed.\n");
+      exit (EXIT_FAILURE);
+    }
+}
+
+int
+main (void)
+{
+  FILE *output;
+
+  output = popen ("more", "w");
+  if (!output)
+    {
+      fprintf (stderr, "Could not run more.\n");
+      return EXIT_FAILURE;
+    }
+  write_data (output);
+  pclose (output);
+  return EXIT_SUCCESS;
+}
diff --git a/manual/examples/rprintf.c b/manual/examples/rprintf.c
new file mode 100644
index 0000000000..c62ff4956e
--- /dev/null
+++ b/manual/examples/rprintf.c
@@ -0,0 +1,56 @@
+#include <stdio.h>
+#include <printf.h>
+#include <stdarg.h>
+
+typedef struct widget
+  {
+    char *name;
+  } Widget;
+
+int 
+print_widget (FILE *stream, const struct printf_info *info, va_list *app)
+{
+  Widget *w;
+  char *buffer;
+  int len, fill, i;
+
+  /* Format the output into a string. */
+  w = va_arg (*app, Widget *);
+  len = asprintf (&buffer, "<Widget %p: %s>", w, w->name);
+  if (len == -1)
+    return -1;
+  fill = info->width - len;
+  if (fill < 0)
+    fill = 0;
+
+  /* Pad to the minimum field width and print to the stream. */
+  if (!info->left)
+    for (i = 0; i < fill; i++)
+      putc (' ', stream);
+  fputs (buffer, stream);
+  if (info->left)
+    for (i = 0; i < fill; i++)
+      putc (' ', stream);
+
+  /* Clean up and return. */
+  free (buffer);
+  return (len + fill);
+}
+
+
+void 
+main (void)
+{
+
+  /* Make a widget to print. */
+  Widget mywidget;
+  mywidget.name = "mywidget";
+
+  /* Register the print function for widgets. */
+  register_printf_function ('W', print_widget);
+
+  /* Now print the widget. */
+  printf ("|%W|\n", &mywidget);
+  printf ("|%35W|\n", &mywidget);
+  printf ("|%-35W|\n", &mywidget);
+}
diff --git a/manual/examples/search.c b/manual/examples/search.c
new file mode 100644
index 0000000000..892290b942
--- /dev/null
+++ b/manual/examples/search.c
@@ -0,0 +1,89 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+/* Define an array of critters to sort. */
+
+struct critter
+{
+  char *name;
+  char *species;
+};
+
+struct critter muppets[]=
+{
+  {"Kermit", "frog"},
+  {"Piggy", "pig"},
+  {"Gonzo", "whatever"},
+  {"Fozzie", "bear"},
+  {"Sam", "eagle"},
+  {"Robin", "frog"},
+  {"Animal", "animal"},
+  {"Camilla", "chicken"},
+  {"Sweetums", "monster"},
+  {"Dr. Strangepork", "pig"},
+  {"Link Hogthrob", "pig"},
+  {"Zoot", "human"},
+  {"Dr. Bunsen Honeydew", "human"},
+  {"Beaker", "human"},
+  {"Swedish Chef", "human"}};
+
+int count = sizeof (muppets) / sizeof (struct critter);
+
+
+
+/* This is the comparison function used for sorting and searching. */
+
+int 
+critter_cmp (const struct critter *c1, const struct critter *c2)
+{
+  return strcmp (c1->name, c2->name);
+}
+
+
+/* Print information about a critter. */
+
+void 
+print_critter (const struct critter *c)
+{
+  printf ("%s, the %s\n", c->name, c->species);
+}
+
+
+/* Do the lookup into the sorted array. */
+
+void 
+find_critter (char *name)
+{
+  struct critter target, *result;
+  target.name = name;
+  result = bsearch (&target, muppets, count, sizeof (struct critter),
+		    critter_cmp);
+  if (result)
+    print_critter (result);
+  else
+    printf ("Couldn't find %s.\n", name);
+}
+
+
+/* Main program. */
+
+void 
+main (void)
+{
+  int i;
+
+  for (i = 0; i < count; i++)
+    print_critter (&muppets[i]);
+  printf ("\n");
+
+  qsort (muppets, count, sizeof (struct critter), critter_cmp);
+
+  for (i = 0; i < count; i++)
+    print_critter (&muppets[i]);
+  printf ("\n");
+
+  find_critter ("Kermit");
+  find_critter ("Gonzo");
+  find_critter ("Janice");
+}
diff --git a/manual/examples/setjmp.c b/manual/examples/setjmp.c
new file mode 100644
index 0000000000..5b5e7d8eda
--- /dev/null
+++ b/manual/examples/setjmp.c
@@ -0,0 +1,32 @@
+#include <setjmp.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+jmp_buf main_loop;
+
+void 
+abort_to_main_loop (int status)
+{
+  longjmp (main_loop, status);
+}
+
+int
+main (void)
+{
+  while (1)
+    if (setjmp (main_loop))
+      printf ("Back at main loop....\n");
+    else
+      do_command ();
+}
+
+
+void 
+do_command (void)
+{
+  char buffer[128];
+  if (fgets (buffer, 128, stdin))
+    abort_to_main_loop (-1);
+  else
+    exit (EXIT_SUCCESS);
+}
diff --git a/manual/examples/sigh1.c b/manual/examples/sigh1.c
new file mode 100644
index 0000000000..909c55b995
--- /dev/null
+++ b/manual/examples/sigh1.c
@@ -0,0 +1,38 @@
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+/* This flag controls termination of the main loop. */
+
+volatile sig_atomic_t keep_going = 1;
+
+
+/* The signal handler just clears the flag and re-enables itself. */
+
+void 
+catch_alarm (int sig)
+{
+  keep_going = 0;
+  signal (sig, catch_alarm);
+}
+
+void 
+do_stuff (void)
+{
+  printf ("Doing stuff while waiting for alarm....\n");
+}
+
+main ()
+{
+
+  /* Establish a handler for SIGALRM signals. */
+  signal (SIGALRM, catch_alarm);
+
+  /* Set an alarm to go off in a little while.  */
+  alarm (2);
+
+  /* Check the flag once in a while to see when to quit. */
+  while (keep_going)
+    do_stuff ();
+  exit (EXIT_SUCCESS);
+}
diff --git a/manual/examples/sigusr.c b/manual/examples/sigusr.c
new file mode 100644
index 0000000000..59e7320235
--- /dev/null
+++ b/manual/examples/sigusr.c
@@ -0,0 +1,60 @@
+#include <signal.h>
+#include <stdio.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+/* When a @code{SIGUSR1} signal arrives, set this variable.  */
+
+volatile sig_atomic_t usr_interrupt = 0;
+
+void 
+synch_signal (int sig)
+{
+  usr_interrupt = 1;
+}
+
+
+/* The child process executes this function. */
+
+void 
+child_function (void)
+{
+  /* Perform initialization. */
+  printf ("I'm here!!!  My pid is %d.\n", (int) getpid ());
+
+  /* Let parent know you're done. */
+  kill (getppid (), SIGUSR1);
+
+  /* Continue with execution. */
+  printf ("Bye, now....\n");
+  exit (0);
+}
+
+
+int
+main (void)
+{
+  struct sigaction usr_action;
+  sigset_t block_mask;
+  pid_t child_id;
+
+  /* Establish the signal handler. */
+  sigfillset (&block_mask);
+  usr_action.sa_handler = synch_signal;
+  usr_action.sa_mask = block_mask;
+  usr_action.sa_flags = 0;
+  sigaction (SIGUSR1, &usr_action, NULL);
+
+  /* Create the child process. */
+  child_id = fork ();
+  if (child_id == 0)
+    child_function ();		/* Does not return */
+
+  /* Busy wait for child to send a signal. */
+  while (!usr_interrupt)
+    ;
+
+  /* Now continue execution. */
+  printf ("That's all, folks!\n");
+  return 0;
+}
diff --git a/manual/examples/strftim.c b/manual/examples/strftim.c
new file mode 100644
index 0000000000..3b27d555c4
--- /dev/null
+++ b/manual/examples/strftim.c
@@ -0,0 +1,29 @@
+#include <time.h>
+#include <stdio.h>
+
+#define SIZE 256
+
+int
+main (void)
+{
+  char buffer[SIZE];
+  time_t curtime;
+  struct tm *loctime;
+
+  /* Get the current time. */
+  curtime = time (NULL);
+
+  /* Convert it to local time representation. */
+  loctime = localtime (&curtime);
+
+  /* Print out the date and time in the standard format. */
+  fputs (asctime (loctime), stdout);
+
+  /* Print it out in a nice format. */
+  strftime (buffer, SIZE, "Today is %A, %B %d.\n", loctime);
+  fputs (buffer, stdout);
+  strftime (buffer, SIZE, "The time is %I:%M %p.\n", loctime);
+  fputs (buffer, stdout);
+
+  return 0;
+}
diff --git a/manual/examples/strncat.c b/manual/examples/strncat.c
new file mode 100644
index 0000000000..c959d40b51
--- /dev/null
+++ b/manual/examples/strncat.c
@@ -0,0 +1,14 @@
+#include <string.h>
+#include <stdio.h>
+
+#define SIZE 10
+
+static char buffer[SIZE];
+
+main ()
+{
+  strncpy (buffer, "hello", SIZE);
+  printf ("%s\n", buffer);
+  strncat (buffer, ", world", SIZE - strlen (buffer) - 1);
+  printf ("%s\n", buffer);
+}
diff --git a/manual/examples/termios.c b/manual/examples/termios.c
new file mode 100644
index 0000000000..ab50cfc586
--- /dev/null
+++ b/manual/examples/termios.c
@@ -0,0 +1,59 @@
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <termios.h>
+
+/* Use this variable to remember original terminal attributes. */
+
+struct termios saved_attributes;
+
+void 
+reset_input_mode (void)
+{
+  tcsetattr (STDIN_FILENO, TCSANOW, &saved_attributes);
+}
+
+void 
+set_input_mode (void)
+{
+  struct termios tattr;
+  char *name;
+
+  /* Make sure stdin is a terminal. */
+  if (!isatty (STDIN_FILENO))
+    {
+      fprintf (stderr, "Not a terminal.\n");
+      exit (EXIT_FAILURE);
+    }
+
+  /* Save the terminal attributes so we can restore them later. */
+  tcgetattr (STDIN_FILENO, &saved_attributes);
+  atexit (reset_input_mode);
+
+  /* Set the funny terminal modes. */
+  tcgetattr (STDIN_FILENO, &tattr);
+  tattr.c_lflag = tattr.c_lflag & (~ICANON);	/* Clear ICANON. */
+  tattr.c_lflag = tattr.c_lflag & (~ECHO);	/* Clear ECHO. */
+  tattr.c_cc[VMIN] = 1;
+  tattr.c_cc[VTIME] = 0;
+  tcsetattr (STDIN_FILENO, TCSAFLUSH, &tattr);
+}
+
+int
+main (void)
+{
+  char c;
+
+  set_input_mode ();
+
+  while (1)
+    {
+      read (STDIN_FILENO, &c, 1);
+      if (c == '\004')
+	break;
+      else
+	putchar (c);
+    }
+
+  return EXIT_SUCCESS;
+}
diff --git a/manual/examples/testopt.c b/manual/examples/testopt.c
new file mode 100644
index 0000000000..e0745429a3
--- /dev/null
+++ b/manual/examples/testopt.c
@@ -0,0 +1,38 @@
+#include <unistd.h>
+#include <stdio.h>
+
+int 
+main (int argc, char **argv)
+{
+  int aflag = 0;
+  int bflag = 0;
+  char *cvalue = NULL;
+  int index;
+  int c;
+
+  while ((c = getopt (argc, argv, "abc:")) >= 0)
+    switch (c)
+      {
+      case 'a':
+	aflag = 1;
+	break;
+      case 'b':
+	bflag = 1;
+	break;
+      case 'c':
+	cvalue = optarg;
+	break;
+      case '?':
+	fprintf (stderr, "Unknown option %c.\n", optopt);
+	return -1;
+      default:
+	fprintf (stderr, "This should never happen!\n");
+	return -1;
+      }
+
+  printf ("aflag = %d, bflag = %d, cvalue = %s\n", aflag, bflag, cvalue);
+
+  for (index = optind; index < argc; index++)
+    printf ("Non-option argument %s\n", argv[index]);
+  return 0;
+}