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explain_fsetpos(3)	   Library Functions Manual	    explain_fsetpos(3)

NAME
       explain_fsetpos - explain fsetpos(3) errors

SYNOPSIS
       #include	<libexplain/fsetpos.h>
       const char *explain_fsetpos(FILE	*fp, fpos_t *pos);
       const char *explain_errno_fsetpos(int errnum, FILE *fp, fpos_t *pos);
       void explain_message_fsetpos(char *message, int message_size, FILE *fp,
       fpos_t *pos);
       void explain_message_errno_fsetpos(char *message, int message_size, int
       errnum, FILE *fp, fpos_t	*pos);

DESCRIPTION
       These  functions	may be used to obtain explanations for errors returned
       by the fsetpos(3) system	call.

   explain_fsetpos
       const char *explain_fsetpos(FILE	*fp, fpos_t *pos);

       The explain_fsetpos function is used to obtain an explanation of	an er-
       ror  returned by	the fsetpos(3) 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.

       fp      The original fp,	exactly	as passed  to  the  fsetpos(3)	system
	       call.

       pos     The  original  pos,  exactly as passed to the fsetpos(3)	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, including
	       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.

       Example:	 This  function	is intended to be used in a fashion similar to
       the following example:
	      if (fsetpos(fp, pos) < 0)
	      {
		  fprintf(stderr, "%s\n", explain_fsetpos(fp, pos));
		  exit(EXIT_FAILURE);
	      }

       The above code example is available pre-packaged	as  the	 explain_fset-
       pos_or_die(3) function.

   explain_errno_fsetpos
       const char *explain_errno_fsetpos(int errnum, FILE *fp, fpos_t *pos);

       The  explain_errno_fsetpos function is used to obtain an	explanation of
       an error	returned by the	fsetpos(3) 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.

       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.

       fp      The original fp,	exactly	as passed  to  the  fsetpos(3)	system
	       call.

       pos     The  original  pos,  exactly as passed to the fsetpos(3)	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, including
	       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.

       Example:	 This  function	is intended to be used in a fashion similar to
       the following example:
	      if (fsetpos(fp, pos) < 0)
	      {
		  int err = errno;
		  fprintf(stderr, "%s\n", explain_errno_fsetpos(err, fp,
		  pos));
		  exit(EXIT_FAILURE);
	      }

       The  above  code	example	is available pre-packaged as the explain_fset-
       pos_or_die(3) function.

   explain_message_fsetpos
       void explain_message_fsetpos(char *message, int message_size, FILE *fp,
       fpos_t *pos);

       The  explain_message_fsetpos  function is used to obtain	an explanation
       of an error returned by the fsetpos(3) system call. The least the  mes-
       sage  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.

       message The location in which to	store the returned message. If a suit-
	       able message return buffer is supplied, this function is	thread
	       safe.

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

       fp      The original fp,	exactly	as passed  to  the  fsetpos(3)	system
	       call.

       pos     The  original  pos,  exactly as passed to the fsetpos(3)	system
	       call.

       Example:	This function is intended to be	used in	a fashion  similar  to
       the following example:
	      if (fsetpos(fp, pos) < 0)
	      {
		  char message[3000];
		  explain_message_fsetpos(message, sizeof(message), fp,	pos);
		  fprintf(stderr, "%s\n", message);
		  exit(EXIT_FAILURE);
	      }

       The  above  code	example	is available pre-packaged as the explain_fset-
       pos_or_die(3) function.

   explain_message_errno_fsetpos
       void explain_message_errno_fsetpos(char *message, int message_size, int
       errnum, FILE *fp, fpos_t	*pos);

       The  explain_message_errno_fsetpos function is used to obtain an	expla-
       nation of an error returned by the fsetpos(3) 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  de-
       tail.

       message The location in which to	store the returned message. If a suit-
	       able message return buffer is 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.

       fp      The original fp,	exactly	as passed  to  the  fsetpos(3)	system
	       call.

       pos     The  original  pos,  exactly as passed to the fsetpos(3)	system
	       call.

       Example:	This function is intended to be	used in	a fashion  similar  to
       the following example:
	      if (fsetpos(fp, pos) < 0)
	      {
		  int err = errno;
		  char message[3000];
		  explain_message_errno_fsetpos(message, sizeof(message), err,
		  fp, pos);
		  fprintf(stderr, "%s\n", message);
		  exit(EXIT_FAILURE);
	      }

       The above code example is available pre-packaged	as  the	 explain_fset-
       pos_or_die(3) function.

SEE ALSO
       fsetpos(3)
	       reposition a stream

       explain_fsetpos_or_die(3)
	       reposition a stream and report errors

COPYRIGHT
       libexplain version 1.3
       Copyright (C) 2010 Peter	Miller

							    explain_fsetpos(3)

NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | COPYRIGHT

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