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explain_lseek(3)	   Library Functions Manual	      explain_lseek(3)

NAME
       explain_lseek - explain lseek(2)	errors

SYNOPSIS
       #include	<libexplain/lseek.h>
       const char *explain_lseek(int fildes, long long offset, int whence);
       const  char *explain_errno_lseek(int errnum, int	fildes,	long long off-
       set, int	whence);
       void explain_message_lseek(char *message, int message_size, int fildes,
       long long offset, int whence);
       void  explain_message_errno_lseek(char  *message, int message_size, int
       errnum, int fildes, long	long offset, int whence);

DESCRIPTION
       These functions may be used to obtain explanations for lseek(2) errors.

   explain_lseek
       const char *explain_lseek(int fildes, long long offset, int whence);

       The explain_lseek function may be used to obtain	a human	 readable  ex-
       planation of what went wrong in an lseek(2) system call.	 The least the
       message will contain is the value of strerror(errno),  but  usually  it
       will do much better, and	indicate the underlying	cause in more detail.

       The  errno global variable will be used to obtain the error value to be
       decoded.

       This function is	intended to be used in a fashion similar to  the  fol-
       lowing example:
	      if (lseek(fd, offset, whence) == (off_t)-1)
	      {
		  fprintf(stderr, '%s0,	explain_lseek(fd, offset, whence);
		  exit(EXIT_FAILURE);
	      }

       fildes  The  original  fildes, exactly as passed	to the lseek(2)	system
	       call.

       offset  The original offset, exactly as passed to the  lseek(2)	system
	       call.

       whence  The  original  whence, exactly as passed	to the lseek(2)	system
	       call.

       Returns:
	       The message explaining  the  error.   This  message  buffer  is
	       shared by all libexplain	functions which	do not supply a	buffer
	       in their	argument list.	This will be overwritten by  the  next
	       call  to	 any libexplain	function which shares this buffer, in-
	       cluding other threads.

       Note: This function is not thread safe, because it shares a return buf-
       fer across all threads, and many	other functions	in this	library.

   explain_errno_lseek
       const  char *explain_errno_lseek(int errnum, int	fildes,	long long off-
       set, int	whence);

       The explain_errno_lseek function	may be used to obtain a	human readable
       explanation  of	what went wrong	in an lseek(2) system call.  The least
       the message will	contain	is the value of	strerror(errnum), but  usually
       it  will	 do much better, and indicate the underlying cause in more de-
       tail.

       This function is	intended to be used in a fashion similar to  the  fol-
       lowing example:
	      if (lseek(fd, offset, whence) == (off_t)-1)
	      {
		  int errnum = errno;
		  fprintf(stderr, '%s0,	explain_errno_lseek(fd,	eernum,	offset,
		      whence);
		  exit(EXIT_FAILURE);
	      }

       errnum  The  error value	to be decoded, usually obtained	from the errno
	       global variable just before this	function is called.   This  is
	       necessary  if you need to call any code between the system call
	       to be explained and this	function, because many libc  functions
	       will alter the value of errno.

       fildes  The  original  fildes, exactly as passed	to the lseek(2)	system
	       call.
	       offset The original offset, exactly as passed to	 the  lseek(2)
	       system call.
	       whence  The  original whence, exactly as	passed to the lseek(2)
	       system call.

       Returns:
	       The message explaining  the  error.   This  message  buffer  is
	       shared by all libexplain	functions which	do not supply a	buffer
	       in their	argument list.	This will be overwritten by  the  next
	       call  to	 any libexplain	function which shares this buffer, in-
	       cluding other threads.

       Note: This function is not thread safe, because it shares a return buf-
       fer across all threads, and many	other functions	in this	library.

   explain_message_lseek
       void explain_message_lseek(char *message, int message_size, int fildes,
       long long offset, int whence);

       The explain_message_lseek function may be used to obtain	a human	 read-
       able  explanation  of  what went	wrong in an lseek(2) system call.  The
       least the message will contain is the  value  of	 strerror(errno),  but
       usually	it  will  do much better, and indicate the underlying cause in
       more detail.

       The errno global	variable will be used to obtain	the error value	to  be
       decoded.

       This  function  is intended to be used in a fashion similar to the fol-
       lowing example:
	      if (lseek(fd, offset, whence) == (off_t)-1)
	      {
		  char message[3000];
		  explain_message_lseek(message, sizeof(message), fd, offset, whence);
		  fprintf(stderr, '%s0,	message);
		  exit(EXIT_FAILURE);
	      }

       message The location in which to	store the returned message.  Because a
	       message	return	buffer	has  been  supplied,  this function is
	       thread safe.

       message_size
	       The size	in bytes of the	location in which  to  store  the  re-
	       turned message.

       fildes  The  original  fildes, exactly as passed	to the lseek(2)	system
	       call.

       offset  The original offset, exactly as passed to the  lseek(2)	system
	       call.

       whence  The  original  whence, exactly as passed	to the lseek(2)	system
	       call.

   explain_message_errno_lseek
       void explain_message_errno_lseek(char *message, int  message_size,  int
       errnum, int fildes, long	long offset, int whence);

       The  explain_message_errno_lseek	function may be	used to	obtain a human
       readable	explanation of what went wrong in  an  lseek(2)	 system	 call.
       The  least  the	message	will contain is	the value of strerror(errnum),
       but usually it will do much better, and indicate	the  underlying	 cause
       in more detail.

       This  function  is intended to be used in a fashion similar to the fol-
       lowing example:
	      if (lseek(fd, offset, whence) == (off_t)-1)
	      {
		  char message[3000];
		  int errnum = errno;
		  explain_message_errno_lseek(message, sizeof(message),	errnum,	fd,
		      offset, whence);
		  fprintf(stderr, '%s0,	message);
		  exit(EXIT_FAILURE);
	      }

       message The location in which to	store the returned message.  Because a
	       message	return	buffer	has  been  supplied,  this function is
	       thread safe.

       message_size
	       The size	in bytes of the	location in which  to  store  the  re-
	       turned message.

       errnum  The  error value	to be decoded, usually obtained	from the errno
	       global variable just before this	function is called.   This  is
	       necessary  if you need to call any code between the system call
	       to be explained and this	function, because many libc  functions
	       will alter the value of errno.

       fildes  The  original  fildes, exactly as passed	to the lseek(2)	system
	       call.

       offset  The orginal offset, exactly as passed to	 the  lseek(2)	system
	       call.

       whence  The  original  whence, exactly as passed	to the lseek(2)	system
	       call.

COPYRIGHT
       libexplain version 1.3
       Copyright (C) 2008 Peter	Miller

AUTHOR
       Written by Peter	Miller <pmiller@opensource.org.au>

							      explain_lseek(3)

NAME | SYNOPSIS | DESCRIPTION | COPYRIGHT | AUTHOR

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