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  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.  * advertising materials, and 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. <<clearerr>>, <<clearerr_unlocked>>---clear file or stream error indicator
  21.  
  22. INDEX
  23.         clearerr
  24. INDEX
  25.         clearerr_unlocked
  26.  
  27. ANSI_SYNOPSIS
  28.         #include <stdio.h>
  29.         void clearerr(FILE *<[fp]>);
  30.  
  31.         #define _BSD_SOURCE
  32.         #include <stdio.h>
  33.         void clearerr_unlocked(FILE *<[fp]>);
  34.  
  35. TRAD_SYNOPSIS
  36.         #include <stdio.h>
  37.         void clearerr(<[fp]>)
  38.         FILE *<[fp]>;
  39.  
  40.         #define _BSD_SOURCE
  41.         #include <stdio.h>
  42.         void clearerr_unlocked(<[fp]>)
  43.         FILE *<[fp]>;
  44.  
  45. DESCRIPTION
  46. The <<stdio>> functions maintain an error indicator with each file
  47. pointer <[fp]>, to record whether any read or write errors have
  48. occurred on the associated file or stream.  Similarly, it maintains an
  49. end-of-file indicator to record whether there is no more data in the
  50. file.
  51.  
  52. Use <<clearerr>> to reset both of these indicators.
  53.  
  54. See <<ferror>> and <<feof>> to query the two indicators.
  55.  
  56. <<clearerr_unlocked>> is a non-thread-safe version of <<clearerr>>.
  57. <<clearerr_unlocked>> may only safely be used within a scope
  58. protected by flockfile() (or ftrylockfile()) and funlockfile().  This
  59. function may safely be used in a multi-threaded program if and only
  60. if they are called while the invoking thread owns the (FILE *)
  61. object, as is the case after a successful call to the flockfile() or
  62. ftrylockfile() functions.  If threads are disabled, then
  63. <<clearerr_unlocked>> is equivalent to <<clearerr>>.
  64.  
  65. RETURNS
  66. <<clearerr>> does not return a result.
  67.  
  68. PORTABILITY
  69. ANSI C requires <<clearerr>>.
  70.  
  71. <<clearerr_unlocked>> is a BSD extension also provided by GNU libc.
  72.  
  73. No supporting OS subroutines are required.
  74. */
  75.  
  76. #include <_ansi.h>
  77. #include <stdio.h>
  78. #include "local.h"
  79.  
  80. /* A subroutine version of the macro clearerr.  */
  81.  
  82. #undef  clearerr
  83.  
  84. _VOID
  85. _DEFUN(clearerr, (fp),
  86.        FILE * fp)
  87. {
  88.   CHECK_INIT(_REENT, fp);
  89.   _newlib_flockfile_start (fp);
  90.   __sclearerr (fp);
  91.   _newlib_flockfile_end (fp);
  92. }
  93.