full_write.c 818 B

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  1. /* vi: set sw=4 ts=4: */
  2. /*
  3. * Utility routines.
  4. *
  5. * Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
  6. *
  7. * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  8. */
  9. #include "libbb.h"
  10. /*
  11. * Write all of the supplied buffer out to a file.
  12. * This does multiple writes as necessary.
  13. * Returns the amount written, or -1 on an error.
  14. */
  15. ssize_t FAST_FUNC full_write(int fd, const void *buf, size_t len)
  16. {
  17. ssize_t cc;
  18. ssize_t total;
  19. total = 0;
  20. while (len) {
  21. cc = safe_write(fd, buf, len);
  22. if (cc < 0) {
  23. if (total) {
  24. /* we already wrote some! */
  25. /* user can do another write to know the error code */
  26. return total;
  27. }
  28. return cc; /* write() returns -1 on failure. */
  29. }
  30. total += cc;
  31. buf = ((const char *)buf) + cc;
  32. len -= cc;
  33. }
  34. return total;
  35. }