Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages

  
 
  

home | help
explain_truncate(3)	   Library Functions Manual	   explain_truncate(3)

NAME
       explain_truncate	- explain truncate(2) errors

SYNOPSIS
       #include	<libexplain/truncate.h>
       const char *explain_truncate(const char *pathname, long long length);
       const  char  *explain_errno_truncate(int	 errnum, const char *pathname,
       long long length);
       void explain_message_truncate(char *message,  int  message_size,	 const
       char *pathname, long long length);
       void  explain_message_errno_truncate(char  *message,  int message_size,
       int errnum, const char *pathname, long long length);

DESCRIPTION
       These functions may be used to obtain explanations for errors  returned
       by the truncate(2) system call.

   explain_truncate
       const char *explain_truncate(const char *pathname, long long length);

       The  explain_truncate  function	is used	to obtain an explanation of an
       error returned by the truncate(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 (truncate(pathname, length) < 0)
	      {
		  fprintf(stderr, "%s\n", explain_truncate(pathname, length));
		  exit(EXIT_FAILURE);
	      }

       pathname
	       The original pathname, exactly as  passed  to  the  truncate(2)
	       system call.

       length  The  original length, exactly as	passed to the truncate(2) sys-
	       tem 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_truncate
       const  char  *explain_errno_truncate(int	 errnum, const char *pathname,
       long long length);

       The explain_errno_truncate function is used to obtain an	explanation of
       an  error  returned by the truncate(2) system call.  The	least the mes-
       sage 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 (truncate(pathname, length) < 0)
	      {
		  int err = errno;
		  fprintf(stderr, "%s\n", explain_errno_truncate(err, pathname,	length));
		  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.

       pathname
	       The original pathname, exactly as  passed  to  the  truncate(2)
	       system call.

       length  The  original length, exactly as	passed to the truncate(2) sys-
	       tem 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_truncate
       void  explain_message_truncate(char  *message,  int message_size, const
       char *pathname, long long length);

       The explain_message_truncate function may be used to  obtain an	expla-
       nation  of an error returned by the truncate(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 de-
       tail.

       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 (truncate(pathname, length) < 0)
	      {
		  char message[3000];
		  explain_message_truncate(message, sizeof(message), pathname, length);
		  fprintf(stderr, "%s\n", message);
		  exit(EXIT_FAILURE);
	      }

       message The location in which to	store  the  returned  message.	 If  a
	       suitable	 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.

       pathname
	       The  original  pathname,	 exactly  as passed to the truncate(2)
	       system call.

       length  The original length, exactly as passed to the truncate(2)  sys-
	       tem call.

   explain_message_errno_truncate
       void  explain_message_errno_truncate(char  *message,  int message_size,
       int errnum, const char *pathname, long long length);

       The explain_message_errno_truncate function may be used	to  obtain  an
       explanation  of	an error returned by the truncate(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 (truncate(pathname, length) < 0)
	      {
		  int err = errno;
		  char message[3000];
		  explain_message_errno_truncate(message, sizeof(message), err,
		      pathname,	length);
		  fprintf(stderr, "%s\n", message);
		  exit(EXIT_FAILURE);
	      }

       message The  location  in  which	 to  store the returned	message.  If a
	       suitable	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.

       pathname
	       The original pathname, exactly as  passed  to  the  truncate(2)
	       system call.

       length  The  original length, exactly as	passed to the truncate(2) sys-
	       tem call.

SEE ALSO
       truncate(2)
	       truncate	a file to a specified length

       explain_truncate_or_die(3)
	       truncate	a file to a specified length and report	errors

COPYRIGHT
       libexplain version 1.3
       Copyright (C) 2008 Peter	Miller

							   explain_truncate(3)

NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | COPYRIGHT

Want to link to this manual page? Use this URL:
<https://www.freebsd.org/cgi/man.cgi?query=explain_truncate&sektion=3&manpath=FreeBSD+12.2-RELEASE+and+Ports>

home | help