lib/libc/stdio/fflush.c

   1 /*
   2  * fflush.c - flush stream(s)
   3  */
   4 /* $Header$ */
   5
   6 #include        <sys/types.h>
   7 #include        <stdio.h>
   8 #include        <errno.h>
   9 #include        "loc_incl.h"
  10
  11 ssize_t _write(int d, const char *buf, size_t nbytes);
  12 off_t _lseek(int fildes, off_t offset, int whence);
  13
  14 int
  15 fflush(FILE *stream)
  16 {
  17         int count, c1, i, retval = 0;
  18
  19         if (!stream) {
  20             for(i= 0; i < FOPEN_MAX; i++)
  21                 if (__iotab[i] && fflush(__iotab[i]))
  22                         retval = EOF;
  23             return retval;
  24         }
  25
  26         if (!stream->_buf
  27             || (!io_testflag(stream, _IOREADING)
  28                 && !io_testflag(stream, _IOWRITING)))
  29                 return 0;
  30         if (io_testflag(stream, _IOREADING)) {
  31                 /* (void) fseek(stream, 0L, SEEK_CUR); */
  32                 int adjust = 0;
  33                 if (io_testflag(stream, _IOFIFO)) {
  34                         /* Can't seek in a pipe. */
  35                         return 0;
  36                 }
  37                 if (stream->_buf && !io_testflag(stream,_IONBF))
  38                         adjust = -stream->_count;
  39                 stream->_count = 0;
  40                 if (_lseek(fileno(stream), (off_t) adjust, SEEK_CUR) == -1 &&
  41                   errno != ESPIPE) {
  42                         stream->_flags |= _IOERR;
  43                         return EOF;
  44                 }
  45                 errno = 0;
  46                 if (io_testflag(stream, _IOWRITE))
  47                         stream->_flags &= ~(_IOREADING | _IOWRITING);
  48                 stream->_ptr = stream->_buf;
  49                 return 0;
  50         } else if (io_testflag(stream, _IONBF)) return 0;
  51
  52         if (io_testflag(stream, _IOREAD))               /* "a" or "+" mode */
  53                 stream->_flags &= ~_IOWRITING;
  54
  55         count = stream->_ptr - stream->_buf;
  56         stream->_ptr = stream->_buf;
  57
  58         if ( count <= 0 )
  59                 return 0;
  60
  61         if (io_testflag(stream, _IOAPPEND)) {
  62                 if (_lseek(fileno(stream), 0L, SEEK_END) == -1) {
  63                         stream->_flags |= _IOERR;
  64                         return EOF;
  65                 }
  66         }
  67         c1 = _write(stream->_fd, (char *)stream->_buf, count);
  68
  69         stream->_count = 0;
  70
  71         if ( count == c1 )
  72                 return 0;
  73
  74         stream->_flags |= _IOERR;
  75         return EOF;
  76 }
  77
  78 void
  79 __cleanup(void)
  80 {
  81         register int i;
  82
  83         for(i= 0; i < FOPEN_MAX; i++)
  84                 if (__iotab[i] && io_testflag(__iotab[i], _IOWRITING))
  85                         (void) fflush(__iotab[i]);
  86 }