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NAME

       explain_fchdir - explain fchdir(2) errors

SYNOPSIS

       #include <libexplain/fchdir.h>
       const char *explain_fchdir(int fildes);
       void   explain_message_fchdir(char   *message,  int  message_size,  int
       fildes);
       const char *explain_errno_fchdir(int errnum, int fildes);
       void explain_message_errno_fchdir(char *message, int message_size,  int
       errnum, int fildes);

DESCRIPTION

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

   explain_fchdir
       const char *explain_fchdir(int fildes);

       The explain_fchdir function is used to  obtain  an  explanation  of  an
       error  returned  by  the  fchdir(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
       following example:
              if (fchdir(fildes) < 0)
              {
                  fprintf(stderr, ’%s0, explain_fchdir(fildes));
                  exit(EXIT_FAILURE);
              }

       fildes  The  original fildes, exactly as passed to the fchdir(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,
               including other threads.

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

   explain_errno_fchdir
       const char *explain_errno_fchdir(int errnum, int fildes);

       The  explain_errno_fchdir  function is used to obtain an explanation of
       an error returned by the fchdir(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
       following example:
              if (fchdir(fildes) < 0)
              {
                  int err = errno;
                  fprintf(stderr, ’%s0, explain_errno_fchdir(err, fildes));
                  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 fchdir(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,
               including other threads.

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

   explain_message_fchdir
       void   explain_message_fchdir(char   *message,  int  message_size,  int
       fildes);

       The explain_message_fchdir function is used to obtain an explanation of
       an  error returned by the fchdir(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
       following example:
              if (fchdir(fildes) < 0)
              {
                  char message[3000];
                  explain_message_fchdir(message, sizeof(message), fildes);
                  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
               returned message.

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

   explain_message_errno_fchdir
       void  explain_message_errno_fchdir(char *message, int message_size, int
       errnum, int fildes);

       The  explain_message_errno_fchdir  function  is  used  to   obtain   an
       explanation  of  an  error  returned by the fchdir(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
       following example:
              if (fchdir(fildes) < 0)
              {
                  int err = errno;
                  char message[3000];
                  explain_message_errno_fchdir(message, sizeof(message), err,
                      fildes);
                  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
               returned 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 fchdir(2)  system
               call.

COPYRIGHT

       libexplain version
       Copyright (C) 2008 Peter Miller

AUTHOR

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

                                                             explain_fchdir(3)