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 1.4
       Copyright (C) 2008 Peter Miller

AUTHOR

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

                                                                                explain_fchdir(3)