newlib/libc/stdio/getchar.c

   1 /*
   2  * Copyright (c) 1990 The Regents of the University of California.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms are permitted
   6  * provided that the above copyright notice and this paragraph are
   7  * duplicated in all such forms and that any documentation,
   8  * and/or other materials related to such
   9  * distribution and use acknowledge that the software was developed
  10  * by the University of California, Berkeley.  The name of the
  11  * University may not be used to endorse or promote products derived
  12  * from this software without specific prior written permission.
  13  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
  14  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  15  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  16  */
  17
  18 /*
  19 FUNCTION
  20 <<getchar>>---read a character (macro)
  21
  22 INDEX
  23         getchar
  24 INDEX
  25         _getchar_r
  26
  27 SYNOPSIS
  28         #include <stdio.h>
  29         int getchar(void);
  30
  31         int _getchar_r(struct _reent *<[reent]>);
  32
  33 DESCRIPTION
  34 <<getchar>> is a macro, defined in <<stdio.h>>.  You can use <<getchar>>
  35 to get the next single character from the standard input stream.
  36 As a side effect, <<getchar>> advances the standard input's
  37 current position indicator.
  38
  39 The alternate function <<_getchar_r>> is a reentrant version.  The
  40 extra argument <[reent]> is a pointer to a reentrancy structure.
  41
  42
  43 RETURNS
  44 The next character (read as an <<unsigned char>>, and cast to
  45 <<int>>), unless there is no more data, or the host system reports a
  46 read error; in either of these situations, <<getchar>> returns <<EOF>>.
  47
  48 You can distinguish the two situations that cause an <<EOF>> result by
  49 using `<<ferror(stdin)>>' and `<<feof(stdin)>>'.
  50
  51 PORTABILITY
  52 ANSI C requires <<getchar>>; it suggests, but does not require, that
  53 <<getchar>> be implemented as a macro.
  54
  55 Supporting OS subroutines required: <<close>>, <<fstat>>, <<isatty>>,
  56 <<lseek>>, <<read>>, <<sbrk>>, <<write>>.
  57 */
  58
  59 #if defined(LIBC_SCCS) && !defined(lint)
  60 static char sccsid[] = "%W% (Berkeley) %G%";
  61 #endif /* LIBC_SCCS and not lint */
  62
  63 /*
  64  * A subroutine version of the macro getchar.
  65  */
  66
  67 #include <_ansi.h>
  68 #include <reent.h>
  69 #include <stdio.h>
  70 #include "local.h"
  71
  72 #undef getchar
  73
  74 int
  75 _getchar_r (struct _reent *reent)
  76 {
  77   _REENT_SMALL_CHECK_INIT (reent);
  78   return _getc_r (reent, _stdin_r (reent));
  79 }
  80
  81 #ifndef _REENT_ONLY
  82
  83 int
  84 getchar (void)
  85 {
  86   struct _reent *reent = _REENT;
  87
  88   /* CHECK_INIT is called (eventually) by __srefill_r.  */
  89   _REENT_SMALL_CHECK_INIT (reent);
  90   return _getc_r (reent, _stdin_r (reent));
  91 }
  92
  93 #endif