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