newlib/libc/stdio/getchar_u.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_unlocked>>---non-thread-safe version of getchar (macro)
  21
  22 INDEX
  23         getchar_unlocked
  24 INDEX
  25         _getchar_unlocked_r
  26
  27 SYNOPSIS
  28         #include <stdio.h>
  29         int getchar_unlocked(void);
  30
  31         #include <stdio.h>
  32         int _getchar_unlocked_r(struct _reent *<[ptr]>);
  33
  34 DESCRIPTION
  35 <<getchar_unlocked>> is a non-thread-safe version of <<getchar>>
  36 declared in <<stdio.h>>.  <<getchar_unlocked>> may only safely be used
  37 within a scope protected by flockfile() (or ftrylockfile()) and
  38 funlockfile().  These functions may safely be used in a multi-threaded
  39 program if and only if they are called while the invoking thread owns
  40 the ( FILE *) object, as is the case after a successful call to the
  41 flockfile() or ftrylockfile() functions.  If threads are disabled,
  42 then <<getchar_unlocked>> is equivalent to <<getchar>>.
  43
  44 The <<_getchar_unlocked_r>> function is simply the reentrant version of
  45 <<getchar_unlocked>> which passes an addtional reentrancy structure pointer
  46 argument: <[ptr]>.
  47
  48 RETURNS
  49 See <<getchar>>.
  50
  51 PORTABILITY
  52 POSIX 1003.1 requires <<getchar_unlocked>>.  <<getchar_unlocked>> may
  53 be implemented as a macro.
  54
  55 Supporting OS subroutines required: <<close>>, <<fstat>>, <<isatty>>,
  56 <<lseek>>, <<read>>, <<sbrk>>, <<write>>.  */
  57
  58 #if defined(LIBC_SCCS) && !defined(lint)
  59 static char sccsid[] = "%W% (Berkeley) %G%";
  60 #endif /* LIBC_SCCS and not lint */
  61
  62 /*
  63  * A subroutine version of the macro getchar_unlocked.
  64  */
  65
  66 #include <_ansi.h>
  67 #include <reent.h>
  68 #include <stdio.h>
  69
  70 #undef getchar_unlocked
  71
  72 int
  73 _getchar_unlocked_r (struct _reent *ptr)
  74 {
  75   return _getc_unlocked_r (ptr, _stdin_r (ptr));
  76 }
  77
  78 #ifndef _REENT_ONLY
  79
  80 int
  81 getchar_unlocked (void)
  82 {
  83   /* CHECK_INIT is called (eventually) by __srefill_r.  */
  84
  85   return _getc_unlocked_r (_REENT, _stdin_r (_REENT));
  86 }
  87
  88 #endif