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explain_fchmod(3)	   Library Functions Manual	     explain_fchmod(3)

NAME
       explain_fchmod -	explain	fchmod(2) errors

SYNOPSIS
       #include	<libexplain/fchmod.h>
       const char *explain_fchmod(int fildes, mode_t mode);
       const char *explain_errno_fchmod(int errnum, int	fildes,	mode_t mode);
       void explain_message_fchmod(char	*message, int message_size, int
       fildes, mode_t mode);
       void explain_message_errno_fchmod(char *message,	int message_size, int
       errnum, int fildes, mode_t mode);

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

   explain_fchmod
       const char *explain_fchmod(int fildes, mode_t mode);

       The explain_fchmod function is used to obtain an	explanation of an  er-
       ror  returned  by the fchmod(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.

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

       mode    The  original  mode,  exactly as	passed to the fchmod(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 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 (fchmod(fildes, mode) < 0)
	      {
		  fprintf(stderr, "%s\n", explain_fchmod(fildes, mode));
		  exit(EXIT_FAILURE);
	      }

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

   explain_errno_fchmod
       const char *explain_errno_fchmod(int errnum, int	fildes,	mode_t mode);

       The  explain_errno_fchmod  function is used to obtain an	explanation of
       an error	returned by the	fchmod(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.

       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 fchmod(2)	system
	       call.

       mode    The  original  mode,  exactly as	passed to the fchmod(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 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 (fchmod(fildes, mode) < 0)
	      {
		  int err = errno;
		  fprintf(stderr, "%s\n", explain_errno_fchmod(err, fildes,
		  mode));
		  exit(EXIT_FAILURE);
	      }

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

   explain_message_fchmod
       void explain_message_fchmod(char	*message, int message_size, int
       fildes, mode_t mode);

       The explain_message_fchmod function is used to obtain an	explanation of
       an error	returned by the	fchmod(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.

       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.

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

       mode    The  original  mode,  exactly as	passed to the fchmod(2)	system
	       call.

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

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

   explain_message_errno_fchmod
       void explain_message_errno_fchmod(char *message,	int message_size, int
       errnum, int fildes, mode_t mode);

       The explain_message_errno_fchmod	function is used to obtain an explana-
       tion  of	 an error returned by the fchmod(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 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.

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

       mode    The  original  mode,  exactly as	passed to the fchmod(2)	system
	       call.

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

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

SEE ALSO
       fchmod(2)
	       change permissions of an	open file

       explain_fchmod_or_die(3)
	       change permissions of an	open file and report errors

COPYRIGHT
       libexplain version 1.3
       Copyright (C) 2013 Peter	Miller

							     explain_fchmod(3)

NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | COPYRIGHT

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