lib_streamsem.c 2.8 KB

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  1. /****************************************************************************
  2. * libs/libc/misc/lib_streamsem.c
  3. *
  4. * Copyright (C) 2007, 2009, 2011, 2017 Gregory Nutt. All rights reserved.
  5. * Author: Gregory Nutt <gnutt@nuttx.org>
  6. *
  7. * Redistribution and use in source and binary forms, with or without
  8. * modification, are permitted provided that the following conditions
  9. * are met:
  10. *
  11. * 1. Redistributions of source code must retain the above copyright
  12. * notice, this list of conditions and the following disclaimer.
  13. * 2. Redistributions in binary form must reproduce the above copyright
  14. * notice, this list of conditions and the following disclaimer in
  15. * the documentation and/or other materials provided with the
  16. * distribution.
  17. * 3. Neither the name NuttX nor the names of its contributors may be
  18. * used to endorse or promote products derived from this software
  19. * without specific prior written permission.
  20. *
  21. * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22. * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  23. * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  24. * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  25. * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  26. * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
  27. * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
  28. * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  29. * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30. * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
  31. * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  32. * POSSIBILITY OF SUCH DAMAGE.
  33. *
  34. ****************************************************************************/
  35. /****************************************************************************
  36. * Included Files
  37. ****************************************************************************/
  38. #include <nuttx/config.h>
  39. #include <stdlib.h>
  40. #include <string.h>
  41. #include <assert.h>
  42. #include <errno.h>
  43. #include <nuttx/semaphore.h>
  44. #include <nuttx/fs/fs.h>
  45. #include "libc.h"
  46. /****************************************************************************
  47. * Public Functions
  48. ****************************************************************************/
  49. void stream_semtake(FAR struct streamlist *list)
  50. {
  51. int ret;
  52. /* Take the semaphore (perhaps waiting) */
  53. while ((ret = _SEM_WAIT(&list->sl_sem)) < 0)
  54. {
  55. /* The only case that an error should occr here is if
  56. * the wait was awakened by a signal.
  57. */
  58. DEBUGASSERT(_SEM_ERRNO(ret) == EINTR || _SEM_ERRNO(ret) == ECANCELED);
  59. UNUSED(ret);
  60. }
  61. }
  62. void stream_semgive(FAR struct streamlist *list)
  63. {
  64. _SEM_POST(&list->sl_sem);
  65. }