diff options
Diffstat (limited to 'manual/examples')
28 files changed, 1190 insertions, 0 deletions
diff --git a/manual/examples/add.c b/manual/examples/add.c new file mode 100644 index 0000000000..e4b1bba365 --- /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 += 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/atexit.c b/manual/examples/atexit.c new file mode 100644 index 0000000000..42bba71126 --- /dev/null +++ b/manual/examples/atexit.c @@ -0,0 +1,15 @@ +#include <stdio.h> +#include <stdlib.h> + +void +bye (void) +{ + puts ("Goodbye, cruel world...."); +} + +int +main (void) +{ + atexit (bye); + exit (EXIT_SUCCESS); +} diff --git a/manual/examples/db.c b/manual/examples/db.c new file mode 100644 index 0000000000..1a1cb0c0d7 --- /dev/null +++ b/manual/examples/db.c @@ -0,0 +1,52 @@ +#include <grp.h> +#include <pwd.h> +#include <sys/types.h> +#include <unistd.h> +#include <stdlib.h> + +int +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 ("I am %s.\n", my_passwd->pw_gecos); + 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++; + } + + return EXIT_SUCCESS; +} diff --git a/manual/examples/dir.c b/manual/examples/dir.c new file mode 100644 index 0000000000..b90f72da03 --- /dev/null +++ b/manual/examples/dir.c @@ -0,0 +1,25 @@ +/*@group*/ +#include <stddef.h> +#include <stdio.h> +#include <sys/types.h> +#include <dirent.h> +/*@end group*/ + +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/filecli.c b/manual/examples/filecli.c new file mode 100644 index 0000000000..b77ae6763e --- /dev/null +++ b/manual/examples/filecli.c @@ -0,0 +1,54 @@ +#include <stdio.h> +#include <errno.h> +#include <unistd.h> +#include <stdlib.h> +#include <sys/socket.h> +#include <sys/un.h> + +#define SERVER "/tmp/serversocket" +#define CLIENT "/tmp/mysocket" +#define MAXMSG 512 +#define MESSAGE "Yow!!! Are we having fun yet?!?" + +int +main (void) +{ + extern int make_named_socket (const char *name); + int sock; + char message[MAXMSG]; + struct sockaddr_un name; + size_t size; + int nbytes; + + /* Make the socket. */ + sock = make_named_socket (CLIENT); + + /* Initialize the server socket address. */ + name.sun_family = AF_UNIX; + strcpy (name.sun_path, SERVER); + size = strlen (name.sun_path) + sizeof (name.sun_family); + + /* Send the datagram. */ + nbytes = sendto (sock, MESSAGE, strlen (MESSAGE) + 1, 0, + (struct sockaddr *) & name, size); + if (nbytes < 0) + { + perror ("sendto (client)"); + exit (EXIT_FAILURE); + } + + /* Wait for a reply. */ + nbytes = recvfrom (sock, message, MAXMSG, 0, NULL, 0); + if (nbytes < 0) + { + perror ("recfrom (client)"); + exit (EXIT_FAILURE); + } + + /* Print a diagnostic message. */ + fprintf (stderr, "Client: got message: %s\n", message); + + /* Clean up. */ + remove (CLIENT); + close (sock); +} diff --git a/manual/examples/filesrv.c b/manual/examples/filesrv.c new file mode 100644 index 0000000000..3596b99982 --- /dev/null +++ b/manual/examples/filesrv.c @@ -0,0 +1,46 @@ +#include <stdio.h> +#include <errno.h> +#include <stdlib.h> +#include <sys/socket.h> +#include <sys/un.h> + +#define SERVER "/tmp/serversocket" +#define MAXMSG 512 + +int +main (void) +{ + int sock; + char message[MAXMSG]; + struct sockaddr_un name; + size_t size; + int nbytes; + + /* Make the socket, then loop endlessly. */ + + sock = make_named_socket (SERVER); + while (1) + { + /* Wait for a datagram. */ + size = sizeof (name); + nbytes = recvfrom (sock, message, MAXMSG, 0, + (struct sockaddr *) & name, &size); + if (nbytes < 0) + { + perror ("recfrom (server)"); + exit (EXIT_FAILURE); + } + + /* Give a diagnostic message. */ + fprintf (stderr, "Server: got message: %s\n", message); + + /* Bounce the message back to the sender. */ + nbytes = sendto (sock, message, nbytes, 0, + (struct sockaddr *) & name, size); + if (nbytes < 0) + { + perror ("sendto (server)"); + exit (EXIT_FAILURE); + } + } +} diff --git a/manual/examples/inetcli.c b/manual/examples/inetcli.c new file mode 100644 index 0000000000..258c6892aa --- /dev/null +++ b/manual/examples/inetcli.c @@ -0,0 +1,59 @@ +#include <stdio.h> +#include <errno.h> +#include <stdlib.h> +#include <unistd.h> +#include <sys/types.h> +#include <sys/socket.h> +#include <netinet/in.h> +#include <netdb.h> + +#define PORT 5555 +#define MESSAGE "Yow!!! Are we having fun yet?!?" +#define SERVERHOST "churchy.gnu.ai.mit.edu" + +void +write_to_server (int filedes) +{ + int nbytes; + + nbytes = write (filedes, MESSAGE, strlen (MESSAGE) + 1); + if (nbytes < 0) + { + perror ("write"); + exit (EXIT_FAILURE); + } +} + + +int +main (void) +{ + extern void init_sockaddr (struct sockaddr_in *name, + const char *hostname, + unsigned short int port); + int sock; + struct sockaddr_in servername; + + /* Create the socket. */ + sock = socket (PF_INET, SOCK_STREAM, 0); + if (sock < 0) + { + perror ("socket (client)"); + exit (EXIT_FAILURE); + } + + /* Connect to the server. */ + init_sockaddr (&servername, SERVERHOST, PORT); + if (0 > connect (sock, + (struct sockaddr *) &servername, + sizeof (servername))) + { + perror ("connect (client)"); + exit (EXIT_FAILURE); + } + + /* Send data to the server. */ + write_to_server (sock); + close (sock); + exit (EXIT_SUCCESS); +} diff --git a/manual/examples/inetsrv.c b/manual/examples/inetsrv.c new file mode 100644 index 0000000000..bd86e80f36 --- /dev/null +++ b/manual/examples/inetsrv.c @@ -0,0 +1,103 @@ +#include <stdio.h> +#include <errno.h> +#include <stdlib.h> +#include <unistd.h> +#include <sys/types.h> +#include <sys/socket.h> +#include <netinet/in.h> +#include <netdb.h> + +#define PORT 5555 +#define MAXMSG 512 + +int +read_from_client (int filedes) +{ + char buffer[MAXMSG]; + int nbytes; + + nbytes = read (filedes, buffer, MAXMSG); + if (nbytes < 0) + { + /* Read error. */ + perror ("read"); + exit (EXIT_FAILURE); + } + else if (nbytes == 0) + /* End-of-file. */ + return -1; + else + { + /* Data read. */ + fprintf (stderr, "Server: got message: `%s'\n", buffer); + return 0; + } +} + +int +main (void) +{ + extern int make_socket (unsigned short int port); + int sock; + fd_set active_fd_set, read_fd_set; + int i; + struct sockaddr_in clientname; + size_t size; + + /* Create the socket and set it up to accept connections. */ + sock = make_socket (PORT); + if (listen (sock, 1) < 0) + { + perror ("listen"); + exit (EXIT_FAILURE); + } + + /* Initialize the set of active sockets. */ + FD_ZERO (&active_fd_set); + FD_SET (sock, &active_fd_set); + + while (1) + { + /* Block until input arrives on one or more active sockets. */ + read_fd_set = active_fd_set; + if (select (FD_SETSIZE, &read_fd_set, NULL, NULL, NULL) < 0) + { + perror ("select"); + exit (EXIT_FAILURE); + } + + /* Service all the sockets with input pending. */ + for (i = 0; i < FD_SETSIZE; ++i) + if (FD_ISSET (i, &read_fd_set)) + { + if (i == sock) + { + /* Connection request on original socket. */ + int new; + size = sizeof (clientname); + new = accept (sock, + (struct sockaddr *) &clientname, + &size); + if (new < 0) + { + perror ("accept"); + exit (EXIT_FAILURE); + } + fprintf (stderr, + "Server: connect from host %s, port %hd.\n", + inet_ntoa (clientname.sin_addr), + ntohs (clientname.sin_port)); + FD_SET (new, &active_fd_set); + } + else + { + /* Data arriving on an already-connected socket. */ + if (read_from_client (i) < 0) + { + close (i); + FD_CLR (i, &active_fd_set); + } + } + } + } +} diff --git a/manual/examples/isockad.c b/manual/examples/isockad.c new file mode 100644 index 0000000000..54ec1cca4c --- /dev/null +++ b/manual/examples/isockad.c @@ -0,0 +1,23 @@ +#include <stdio.h> +#include <stdlib.h> +#include <sys/socket.h> +#include <netinet/in.h> +#include <netdb.h> + +void +init_sockaddr (struct sockaddr_in *name, + const char *hostname, + unsigned short int port) +{ + struct hostent *hostinfo; + + name->sin_family = AF_INET; + name->sin_port = htons (port); + hostinfo = gethostbyname (hostname); + if (hostinfo == NULL) + { + fprintf (stderr, "Unknown host %s.\n", hostname); + exit (EXIT_FAILURE); + } + name->sin_addr = *(struct in_addr *) hostinfo->h_addr; +} diff --git a/manual/examples/longopt.c b/manual/examples/longopt.c new file mode 100644 index 0000000000..d5c841f24a --- /dev/null +++ b/manual/examples/longopt.c @@ -0,0 +1,92 @@ +#include <stdio.h> + +/* Flag set by @samp{--verbose}. */ +static int verbose_flag; + +int +main (argc, argv) + int argc; + char **argv; +{ + int c; + + while (1) + { + static struct option long_options[] = + { + /* These options set a flag. */ + {"verbose", 0, &verbose_flag, 1}, + {"brief", 0, &verbose_flag, 0}, + /* These options don't set a flag. + We distinguish them by their indices. */ + {"add", 1, 0, 0}, + {"append", 0, 0, 0}, + {"delete", 1, 0, 0}, + {"create", 0, 0, 0}, + {"file", 1, 0, 0}, + {0, 0, 0, 0} + }; + /* @code{getopt_long} stores the option index here. */ + int option_index = 0; + + c = getopt_long (argc, argv, "abc:d:", + long_options, &option_index); + + /* Detect the end of the options. */ + if (c == -1) + break; + + switch (c) + { + case 0: + /* If this option set a flag, do nothing else now. */ + if (long_options[option_index].flag != 0) + break; + printf ("option %s", long_options[option_index].name); + if (optarg) + printf (" with arg %s", optarg); + printf ("\n"); + break; + + case 'a': + puts ("option -a\n"); + break; + + case 'b': + puts ("option -b\n"); + break; + + case 'c': + printf ("option -c with value `%s'\n", optarg); + break; + + case 'd': + printf ("option -d with value `%s'\n", optarg); + break; + + case '?': + /* @code{getopt_long} already printed an error message. */ + break; + + default: + abort (); + } + } + + /* Instead of reporting @samp{--verbose} + and @samp{--brief} as they are encountered, + we report the final status resulting from them. */ + if (verbose_flag) + puts ("verbose flag is set"); + + /* Print any remaining command line arguments (not options). */ + if (optind < argc) + { + printf ("non-option ARGV-elements: "); + while (optind < argc) + printf ("%s ", argv[optind++]); + putchar ('\n'); + } + + exit (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..1674c36e0b --- /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/mkfsock.c b/manual/examples/mkfsock.c new file mode 100644 index 0000000000..d3750ec150 --- /dev/null +++ b/manual/examples/mkfsock.c @@ -0,0 +1,43 @@ +#include <stddef.h> +#include <stdio.h> +#include <errno.h> +#include <stdlib.h> +#include <sys/socket.h> +#include <sys/un.h> + +int +make_named_socket (const char *filename) +{ + struct sockaddr_un name; + int sock; + size_t size; + + /* Create the socket. */ + + sock = socket (PF_UNIX, SOCK_DGRAM, 0); + if (sock < 0) + { + perror ("socket"); + exit (EXIT_FAILURE); + } + + /* Bind a name to the socket. */ + + name.sun_family = AF_FILE; + strcpy (name.sun_path, filename); + + /* The size of the address is + the offset of the start of the filename, + plus its length, + plus one for the terminating null byte. */ + size = (offsetof (struct sockaddr_un, sun_path) + + strlen (name.sun_path) + 1); + + if (bind (sock, (struct sockaddr *) &name, size) < 0) + { + perror ("bind"); + exit (EXIT_FAILURE); + } + + return sock; +} diff --git a/manual/examples/mkisock.c b/manual/examples/mkisock.c new file mode 100644 index 0000000000..07411bb263 --- /dev/null +++ b/manual/examples/mkisock.c @@ -0,0 +1,31 @@ +#include <stdio.h> +#include <stdlib.h> +#include <sys/socket.h> +#include <netinet/in.h> + +int +make_socket (unsigned short int port) +{ + int sock; + struct sockaddr_in name; + + /* Create the socket. */ + sock = socket (PF_INET, SOCK_STREAM, 0); + if (sock < 0) + { + perror ("socket"); + exit (EXIT_FAILURE); + } + + /* Give the socket a name. */ + name.sin_family = AF_INET; + name.sin_port = htons (port); + name.sin_addr.s_addr = htonl (INADDR_ANY); + if (bind (sock, (struct sockaddr *) &name, sizeof (name)) < 0) + { + perror ("bind"); + exit (EXIT_FAILURE); + } + + return sock; +} diff --git a/manual/examples/pipe.c b/manual/examples/pipe.c new file mode 100644 index 0000000000..054550fec6 --- /dev/null +++ b/manual/examples/pipe.c @@ -0,0 +1,66 @@ +#include <sys/types.h> +#include <unistd.h> +#include <stdio.h> +#include <stdlib.h> + +/* Read characters from the pipe and echo them to @code{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]; + +/*@group*/ + /* Create the pipe. */ + if (pipe (mypipe)) + { + fprintf (stderr, "Pipe failed.\n"); + return EXIT_FAILURE; + } +/*@end group*/ + + /* 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..16ae32fa16 --- /dev/null +++ b/manual/examples/popen.c @@ -0,0 +1,33 @@ +#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); + } +} + +/*@group*/ +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; +} +/*@end group*/ diff --git a/manual/examples/rprintf.c b/manual/examples/rprintf.c new file mode 100644 index 0000000000..eff1d8e7cf --- /dev/null +++ b/manual/examples/rprintf.c @@ -0,0 +1,52 @@ +#include <stdio.h> +#include <printf.h> +#include <stdarg.h> + +/*@group*/ +typedef struct + { + char *name; + } Widget; +/*@end group*/ + +int +print_widget (FILE *stream, const struct printf_info *info, va_list *app) +{ + Widget *w; + char *buffer; + int len; + + /* 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; + + /* Pad to the minimum field width and print to the stream. */ + len = fprintf (stream, "%*s", + (info->left ? - info->width : info->width), + buffer); + + /* Clean up and return. */ + free (buffer); + return len; +} + + +int +main (void) +{ + /* Make a widget to print. */ + Widget mywidget; + mywidget.name = "mywidget"; + + /* Register the print function for widgets. */ + register_printf_function ('W', print_widget, NULL); /* No arginfo. */ + + /* Now print the widget. */ + printf ("|%W|\n", &mywidget); + printf ("|%35W|\n", &mywidget); + printf ("|%-35W|\n", &mywidget); + + return 0; +} diff --git a/manual/examples/search b/manual/examples/search Binary files differnew file mode 100755 index 0000000000..4916a2c52f --- /dev/null +++ b/manual/examples/search diff --git a/manual/examples/search.c b/manual/examples/search.c new file mode 100644 index 0000000000..182e6e4a3f --- /dev/null +++ b/manual/examples/search.c @@ -0,0 +1,93 @@ +#include <stdlib.h> +#include <stdio.h> +#include <string.h> + +/* Define an array of critters to sort. */ + +struct critter + { + const char *name; + const 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); +} + + +/*@group*/ +/* Do the lookup into the sorted array. */ + +void +find_critter (const 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); +} +/*@end group*/ + +/* Main program. */ + +int +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"); + + return 0; +} diff --git a/manual/examples/select.c b/manual/examples/select.c new file mode 100644 index 0000000000..def2cd6f9f --- /dev/null +++ b/manual/examples/select.c @@ -0,0 +1,40 @@ +/*@group*/ +#include <stdio.h> +#include <unistd.h> +#include <sys/types.h> +#include <sys/time.h> +/*@end group*/ + +/*@group*/ +int +input_timeout (int filedes, unsigned int seconds) +{ + fd_set set; + struct timeval timeout; +/*@end group*/ + + /* Initialize the file descriptor set. */ + FD_ZERO (&set); + FD_SET (filedes, &set); + + /* Initialize the timeout data structure. */ + timeout.tv_sec = seconds; + timeout.tv_usec = 0; + +/*@group*/ + /* @code{select} returns 0 if timeout, 1 if input available, -1 if error. */ + return TEMP_FAILURE_RETRY (select (FD_SETSIZE, + &set, NULL, NULL, + &timeout)); +} +/*@end group*/ + +/*@group*/ +int +main (void) +{ + fprintf (stderr, "select returned %d.\n", + input_timeout (STDIN_FILENO, 5)); + return 0; +} +/*@end group*/ diff --git a/manual/examples/setjmp.c b/manual/examples/setjmp.c new file mode 100644 index 0000000000..023339c602 --- /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)) + puts ("Back at main loop...."); + else + do_command (); +} + + +void +do_command (void) +{ + char buffer[128]; + if (fgets (buffer, 128, stdin) == NULL) + 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..2c6e95b9c9 --- /dev/null +++ b/manual/examples/sigh1.c @@ -0,0 +1,36 @@ +#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) +{ + puts ("Doing stuff while waiting for alarm...."); +} + +int +main (void) +{ + /* 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 (); + + return EXIT_SUCCESS; +} diff --git a/manual/examples/sigusr.c b/manual/examples/sigusr.c new file mode 100644 index 0000000000..11e3ceee8f --- /dev/null +++ b/manual/examples/sigusr.c @@ -0,0 +1,61 @@ +/*@group*/ +#include <signal.h> +#include <stdio.h> +#include <sys/types.h> +#include <unistd.h> +/*@end group*/ + +/* 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. */ + puts ("Bye, now...."); + 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. */ + +/*@group*/ + /* Busy wait for the child to send a signal. */ + while (!usr_interrupt) + ; +/*@end group*/ + + /* Now continue execution. */ + puts ("That's all, folks!"); + + return 0; +} diff --git a/manual/examples/stpcpy.c b/manual/examples/stpcpy.c new file mode 100644 index 0000000000..b83226354b --- /dev/null +++ b/manual/examples/stpcpy.c @@ -0,0 +1,13 @@ +#include <string.h> +#include <stdio.h> + +int +main (void) +{ + char buffer[10]; + char *to = buffer; + to = stpcpy (to, "foo"); + to = stpcpy (to, "bar"); + puts (buffer); + return 0; +} diff --git a/manual/examples/strftim.c b/manual/examples/strftim.c new file mode 100644 index 0000000000..7f95ef02ad --- /dev/null +++ b/manual/examples/strftim.c @@ -0,0 +1,31 @@ +#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); + +/*@group*/ + /* 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; +} +/*@end group*/ diff --git a/manual/examples/strncat.c b/manual/examples/strncat.c new file mode 100644 index 0000000000..f865167f4a --- /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); + puts (buffer); + strncat (buffer, ", world", SIZE - strlen (buffer) - 1); + puts (buffer); +} diff --git a/manual/examples/termios.c b/manual/examples/termios.c new file mode 100644 index 0000000000..6db5990a0c --- /dev/null +++ b/manual/examples/termios.c @@ -0,0 +1,60 @@ +#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); + +/*@group*/ + /* Set the funny terminal modes. */ + tcgetattr (STDIN_FILENO, &tattr); + tattr.c_lflag &= ~(ICANON|ECHO); /* Clear ICANON and ECHO. */ + tattr.c_cc[VMIN] = 1; + tattr.c_cc[VTIME] = 0; + tcsetattr (STDIN_FILENO, TCSAFLUSH, &tattr); +} +/*@end group*/ + +int +main (void) +{ + char c; + + set_input_mode (); + + while (1) + { + read (STDIN_FILENO, &c, 1); + if (c == '\004') /* @kbd{C-d} */ + 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..8ebc9b6f7a --- /dev/null +++ b/manual/examples/testopt.c @@ -0,0 +1,50 @@ +/*@group*/ +#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; + + opterr = 0; +/*@end group*/ + +/*@group*/ + while ((c = getopt (argc, argv, "abc:")) != -1) + switch (c) + { + case 'a': + aflag = 1; + break; + case 'b': + bflag = 1; + break; + case 'c': + cvalue = optarg; + break; + case '?': + if (isprint (optopt)) + fprintf (stderr, "Unknown option `-%c'.\n", optopt); + else + fprintf (stderr, + "Unknown option character `\\x%x'.\n", + optopt); + return 1; + default: + abort (); + } +/*@end group*/ + +/*@group*/ + 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; +} +/*@end group*/ |