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