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explain_fstatfs(3)	    Library Functions Manual	      explain_fstatfs(3)

NAME
     explain_fstatfs - explain fstatfs(2) errors

SYNOPSIS
     #include <libexplain/fstatfs.h>
     const char *explain_fstatfs(int fildes, struct statfs *data);
     const char *explain_errno_fstatfs(int errnum, int fildes, struct statfs
     *data);
     void explain_message_fstatfs(char *message, int message_size, int fildes,
     struct statfs *data);
     void explain_message_errno_fstatfs(char *message, int message_size, int er-
     rnum, int fildes, struct statfs *data);

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

   explain_fstatfs
     const char *explain_fstatfs(int fildes, struct statfs *data);

     The explain_fstatfs function is used to obtain an explanation of  an  error
     returned  by the fstatfs(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 de-
     coded.

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

     data    The original data, exactly as passed to the fstatfs(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  ar-
	     gument list.  This will be overwritten by the next call to any lib-
	     explain 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.

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

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

   explain_errno_fstatfs
     const char *explain_errno_fstatfs(int errnum, int fildes, struct statfs
     *data);

     The explain_errno_fstatfs function is used to obtain an explanation  of  an
     error  returned  by  the fstatfs(2) system call. The least the message will
     contain is the value of strerror(errno), but usually it will do  much  bet-
     ter, 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 neces-
	     sary if you need to call any code between the system call to be ex-
	     plained and this function, because many libc functions  will  alter
	     the value of errno.

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

     data    The original data, exactly as passed to the fstatfs(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 ar-
	     gument list.  This will be overwritten by the next call to any lib-
	     explain 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.

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

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

   explain_message_fstatfs
     void explain_message_fstatfs(char *message, int message_size, int fildes,
     struct statfs *data);

     The explain_message_fstatfs function is used to obtain an explanation of an
     error  returned  by  the fstatfs(2) system call. The least the message will
     contain is the value of strerror(errno), but usually it will do  much  bet-
     ter, and indicate the underlying cause in more detail.

     The  errno global variable will be used to obtain the error value to be de-
     coded.

     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 returned
	     message.

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

     data    The original data, exactly as passed to the fstatfs(2) system call.

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

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

   explain_message_errno_fstatfs
     void explain_message_errno_fstatfs(char *message, int message_size, int er-
     rnum, int fildes, struct statfs *data);

     The explain_message_errno_fstatfs function is used to obtain an explanation
     of  an  error returned by the fstatfs(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.

     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	returned
	     message.

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

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

     data    The original data, exactly as passed to the fstatfs(2) system call.

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

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

SEE ALSO
     fstatfs(2)
	     get file system statistics

     explain_fstatfs_or_die(3)
	     get file system statistics and report errors

COPYRIGHT
     libexplain version 1.3
     Copyright (C) 2009 Peter Miller

							      explain_fstatfs(3)

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