reactos/lib/msvcrt/stdio/fflush.c

   1 /*
   2  * COPYRIGHT:   See COPYING in the top level directory
   3  * PROJECT:     ReactOS system libraries
   4  * FILE:        lib/crtdll/conio/kbhit.c
   5  * PURPOSE:     Checks for keyboard hits
   6  * PROGRAMER:   Boudewijn Dekker
   7  * UPDATE HISTORY:
   8  *              28/12/98: Created
   9  */
  10 /* Copyright (C) 1998 DJ Delorie, see COPYING.DJ for details */
  11 /* Copyright (C) 1996 DJ Delorie, see COPYING.DJ for details */
  12 /* Copyright (C) 1995 DJ Delorie, see COPYING.DJ for details */
  13
  14 #include <msvcrt/stdio.h>
  15 #include <msvcrt/errno.h>
  16 #include <msvcrt/sys/types.h>
  17 #include <msvcrt/sys/stat.h>
  18 #include <msvcrt/stdlib.h>
  19 #include <msvcrt/internal/file.h>
  20 #include <msvcrt/io.h>
  21
  22
  23 int fflush(FILE *f)
  24 {
  25   char *base;
  26   int n, rn;
  27
  28
  29
  30   if (f == NULL)
  31   {
  32      int e = errno;
  33
  34      __set_errno(0);
  35     _fwalk((void (*)(FILE *))fflush);
  36     if (_errno)
  37       return EOF;
  38     __set_errno(e);
  39     return 0;
  40   }
  41
  42
  43 // nothing to do if stream can not be written to
  44
  45   if ( !OPEN4WRITING(f) ) {
  46         __set_errno (EINVAL);
  47         return 0;
  48   }
  49
  50 // discard any unget characters
  51
  52   f->_flag &= ~_IOUNGETC;
  53
  54
  55 // check for buffered dirty block
  56
  57   if ( (f->_flag&(_IODIRTY|_IONBF)) ==_IODIRTY && f->_base != NULL)
  58   {
  59
  60     base = f->_base;
  61
  62
  63 // if the buffer is read ahead and dirty we will flush it entirely
  64 // else the buffer is appended to the file to the extend it has valid bytes
  65
  66     if ( (f->_flag & _IOAHEAD) == _IOAHEAD )
  67         rn = n = f->_ptr - base + f->_cnt;
  68     else
  69         rn = n = f->_ptr - base;
  70
  71     f->_ptr = base;
  72
  73     if ((f->_flag & _IOFBF) == _IOFBF) {
  74         if ( (f->_flag & _IOAHEAD) == _IOAHEAD )
  75             _lseek(fileno(f),-rn, SEEK_CUR);
  76     }
  77
  78     f->_flag &= ~_IOAHEAD;
  79
  80
  81     f->_cnt = (f->_flag&(_IOLBF|_IONBF)) ? 0 : f->_bufsiz;
  82
  83 // how can write return less than rn without being on error ???
  84
  85 // possibly commit the flushed data
  86 // better open the file in write through mode
  87
  88     while (rn > 0) {
  89       n = _write(fileno(f), base, rn);
  90       if (n <= 0) {
  91             f->_flag |= _IOERR;
  92             return EOF;
  93       }
  94       rn -= n;
  95       base += n;
  96     };
  97     f->_flag &= ~_IODIRTY;
  98
  99   }
 100   if (OPEN4READING(f) && OPEN4WRITING(f) )
 101   {
 102     f->_cnt = 0;
 103     f->_ptr = f->_base;
 104   }
 105   return 0;
 106 }
 107
 108 int _flushall( void )
 109 {
 110         return fflush(NULL);
 111 }