diplodocus.org Git - nmh/blob - sbr/getans.c

   1
   2 /*
   3  * getans.c -- get an answer from the user and return a string array
   4  *
   5  * This code is Copyright (c) 2002, by the authors of nmh.  See the
   6  * COPYRIGHT file in the root directory of the nmh distribution for
   7  * complete copyright information.
   8  */
   9
  10 #include <h/mh.h>
  11 #include <h/signals.h>
  12 #include <setjmp.h>
  13 #include <signal.h>
  14 #include <errno.h>
  15
  16 static char ansbuf[BUFSIZ];
  17 static sigjmp_buf sigenv;
  18
  19 /*
  20  * static prototypes
  21  */
  22 static void intrser (int);
  23
  24
  25 char **
  26 getans (char *prompt, struct swit *ansp)
  27 {
  28     int i;
  29     SIGNAL_HANDLER istat = NULL;
  30     char *cp, **cpp;
  31
  32     if (!(sigsetjmp(sigenv, 1))) {
  33         istat = SIGNAL (SIGINT, intrser);
  34     } else {
  35         SIGNAL (SIGINT, istat);
  36         return NULL;
  37     }
  38
  39     for (;;) {
  40         printf ("%s", prompt);
  41         fflush (stdout);
  42         cp = ansbuf;
  43         while ((i = getchar ()) != '\n') {
  44             if (i == EOF) {
  45                 /*
  46                  * If we get an EOF, return
  47                  */
  48                 if (feof(stdin))
  49                     siglongjmp (sigenv, 1);
  50
  51                 /*
  52                  * For errors, if we get an EINTR that means that we got
  53                  * a signal and we should retry.  If we get another error,
  54                  * then just return.
  55                  */
  56
  57                 else if (ferror(stdin)) {
  58                     if (errno == EINTR) {
  59                         clearerr(stdin);
  60                         continue;
  61                     }
  62                     fprintf(stderr, "\nError %s during read\n",
  63                             strerror(errno));
  64                     siglongjmp (sigenv, 1);
  65                 } else {
  66                     /*
  67                      * Just for completeness's sake ...
  68                      */
  69
  70                     fprintf(stderr, "\nUnknown problem in getchar()\n");
  71                     siglongjmp (sigenv, 1);
  72                 }
  73             }
  74             if (cp < &ansbuf[sizeof ansbuf - 1])
  75                 *cp++ = i;
  76         }
  77         *cp = '\0';
  78         if (ansbuf[0] == '?' || cp == ansbuf) {
  79             printf ("Options are:\n");
  80             print_sw (ALL, ansp, "", stdout);
  81             continue;
  82         }
  83         cpp = brkstring (ansbuf, " ", NULL);
  84         switch (smatch (*cpp, ansp)) {
  85             case AMBIGSW:
  86                 ambigsw (*cpp, ansp);
  87                 continue;
  88             case UNKWNSW:
  89                 printf (" -%s unknown. Hit <CR> for help.\n", *cpp);
  90                 continue;
  91             default:
  92                 SIGNAL (SIGINT, istat);
  93                 return cpp;
  94         }
  95     }
  96 }
  97
  98
  99 static void
 100 intrser (int i)
 101 {
 102     NMH_UNUSED (i);
 103
 104     /*
 105      * should this be siglongjmp?
 106      */
 107     siglongjmp (sigenv, 1);
 108 }