source: rtems/c/src/exec/libcsupport/src/read.c @ e22d644

4.104.114.84.9
Last change on this file since e22d644 was e22d644, checked in by Joel Sherrill <joel.sherrill@…>, on Dec 14, 1998 at 11:01:43 PM

Corrected prototype to confirm to POSIX 1003.1b.

  • Property mode set to 100644
File size: 1.7 KB
Line 
1/*
2 *  read() - POSIX 1003.1b 6.4.1 - Read From a File
3 *
4 *  COPYRIGHT (c) 1989-1998.
5 *  On-Line Applications Research Corporation (OAR).
6 *  Copyright assigned to U.S. Government, 1994.
7 *
8 *  The license and distribution terms for this file may be
9 *  found in the file LICENSE in this distribution or at
10 *  http://www.OARcorp.com/rtems/license.html.
11 *
12 *  $Id$
13 */
14
15#include "libio_.h"
16
17ssize_t read(
18  int         fd,
19  void       *buffer,
20  size_t      count
21)
22{
23  int             rc;  /* XXX change to a size_t when prototype is fixed */
24  rtems_libio_t *iop;
25
26  rtems_libio_check_fd( fd );
27  iop = rtems_libio_iop( fd );
28  rtems_libio_check_buffer( buffer );
29  rtems_libio_check_count( count );
30  rtems_libio_check_permissions( iop, LIBIO_FLAGS_READ );
31
32  /*
33   *  If this file descriptor is mapped to an external set of handlers,
34   *  then pass the request on to them.
35   */ 
36
37  if ( iop->flags & LIBIO_FLAGS_HANDLER_MASK ) {
38    rtems_libio_read_t fp;
39
40    fp = rtems_libio_handlers[
41           (iop->flags >> LIBIO_FLAGS_HANDLER_SHIFT) - 1].read;
42    if ( fp == NULL )
43      set_errno_and_return_minus_one( EBADF );
44
45    return (*fp)( fd, buffer, count );
46  }
47
48  /*
49   *  Now process the read().
50   */
51
52  if ( !iop->handlers->read )
53    set_errno_and_return_minus_one( ENOTSUP );
54
55  rc = (*iop->handlers->read)( iop, buffer, count );
56
57  if ( rc > 0 )
58    iop->offset += rc;
59
60  return rc;
61}
62
63/*
64 *  _read_r
65 *
66 *  This is the Newlib dependent reentrant version of read().
67 */
68
69#if defined(RTEMS_NEWLIB)
70
71#include <reent.h>
72
73_ssize_t _read_r(
74  struct _reent *ptr,
75  int            fd,
76  void          *buf,
77  size_t         nbytes
78)
79{
80  return read( fd, buf, nbytes );
81}
82#endif
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