compiler/stdc/snprintf.c

   1 /*
   2     Copyright © 1995-2012, The AROS Development Team. All rights reserved.
   3     $Id$
   4
   5     C99 function snprintf().
   6 */
   7
   8 #define DEBUG 0
   9 #include <aros/debug.h>
  10
  11 /*****************************************************************************
  12
  13     NAME */
  14 #include <stdio.h>
  15
  16         int snprintf (
  17
  18 /*  SYNOPSIS */
  19         char       * str,
  20         size_t       n,
  21         const char * format,
  22         ...)
  23
  24 /*  FUNCTION
  25         C99 says:The snprintf function is equivalent to fprintf, except that the output is
  26         written into an array (specified by argument s) rather than to a stream. If
  27         n is zero, nothing is written, and s may be a null pointer. Otherwise,
  28         output characters beyond the n-1st are discarded rather than being written
  29         to the array, and a null character is written at the end of the characters
  30         actually written into the array. If copying takes place between objects
  31         that overlap, the behavior is undefined.
  32
  33     INPUTS
  34         str - The formatted string is written into this variable. You
  35               must make sure that it is large enough to contain the
  36               result.
  37         n -   At most n characters are written into the string. This
  38               includes the final 0.
  39         format - Format string as described above
  40         ... - Arguments for the format string
  41
  42     RESULT
  43         The snprintf function returns the number of characters that would have been
  44         written had n been sufficiently large, not counting the terminating null
  45         character, or a negative value if an encoding error occurred. Thus, the
  46         null-terminated output has been completely written if and only if the
  47         returned value is nonnegative and less than n.
  48
  49     NOTES
  50
  51     EXAMPLE
  52
  53     BUGS
  54
  55     SEE ALSO
  56         fprintf(), vprintf(), vfprintf(), snprintf(), vsprintf(),
  57         vsnprintf()
  58
  59     INTERNALS
  60
  61 ******************************************************************************/
  62 {
  63     int     retval;
  64     va_list args;
  65
  66     D(bug("[snprintf] start; str %p('%s'), format: %p('%s')\n",
  67           str, str, format, format
  68     ));
  69
  70     va_start (args, format);
  71
  72     retval = vsnprintf (str, n, format, args);
  73
  74     va_end (args);
  75
  76     D(bug("[snprintf] end; str %p('%s'), format: %p('%s')\n",
  77           str, str, format, format
  78     ));
  79
  80     return retval;
  81 } /* snprintf */
  82
  83 #ifdef TEST
  84 #include <stdio.h>
  85
  86 int main (int argc, char ** argv)
  87 {
  88     char buffer[11];
  89     int  rc;
  90
  91     printf ("snprintf test\n");
  92
  93     rc = snprintf (buffer, sizeof (buffer), "%10d", 5);
  94
  95     if (rc < sizeof (buffer))
  96         printf ("rc=%d, buffer=\"%s\"\n", rc, buffer);
  97     else
  98         printf ("rc=%d\n", rc);
  99
 100     rc = snprintf (buffer, sizeof (buffer), "%11d", 5);
 101
 102     if (rc < sizeof (buffer))
 103         printf ("rc=%d, buffer=\"%s\"\n", rc, buffer);
 104     else
 105         printf ("rc=%d\n", rc);
 106
 107     return 0;
 108 } /* main */
 109
 110 #endif /* TEST */