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explain_mmap(3)		   Library Functions Manual	       explain_mmap(3)

NAME
       explain_mmap - explain mmap(2) errors

SYNOPSIS
       #include	<libexplain/mmap.h>
       const char *explain_mmap(void *data, size_t data_size, int prot,	int
       flags, int fildes, off_t	offset);
       const char *explain_errno_mmap(int errnum, void *data, size_t
       data_size, int prot, int	flags, int fildes, off_t offset);
       void explain_message_mmap(char *message,	int message_size, void *data,
       size_t data_size, int prot, int flags, int fildes, off_t	offset);
       void explain_message_errno_mmap(char *message, int message_size,	int
       errnum, void *data, size_t data_size, int prot, int flags, int fildes,
       off_t offset);

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

   explain_mmap
       const char *explain_mmap(void *data, size_t data_size, int prot,	int
       flags, int fildes, off_t	offset);

       The explain_mmap	function is used to obtain an explanation of an	 error
       returned	by the mmap(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.

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

       data_size
	       The original data_size, exactly as passed to the	mmap(2)	system
	       call.

       prot    The original prot, exactly as  passed  to  the  mmap(2)	system
	       call.

       flags   The  original  flags,  exactly  as passed to the	mmap(2)	system
	       call.

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

       offset  The  original  offset,  exactly as passed to the	mmap(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:
	      void *result = mmap(data,	data_size, prot, flags,	fildes,	off-
	      set);
	      if (!result)
	      {
		  fprintf(stderr, "%s\n", explain_mmap(data, data_size,	prot,
		  flags, fildes, offset));
		  exit(EXIT_FAILURE);
	      }

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

   explain_errno_mmap
       const char *explain_errno_mmap(int errnum, void *data, size_t
       data_size, int prot, int	flags, int fildes, off_t offset);

       The explain_errno_mmap function is used to obtain an explanation	of  an
       error  returned	by the mmap(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.

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

       data_size
	       The original data_size, exactly as passed to the	mmap(2)	system
	       call.

       prot    The  original  prot,  exactly  as  passed to the	mmap(2)	system
	       call.

       flags   The original flags, exactly as passed  to  the  mmap(2)	system
	       call.

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

       offset  The original offset, exactly as passed to  the  mmap(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:
	      void *result = mmap(data,	data_size, prot, flags,	fildes,	off-
	      set);
	      if (!result)
	      {
		  int err = errno;
		  fprintf(stderr, "%s\n", explain_errno_mmap(err, data,
		  data_size, prot, flags, fildes, offset));
		  exit(EXIT_FAILURE);
	      }

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

   explain_message_mmap
       void explain_message_mmap(char *message,	int message_size, void *data,
       size_t data_size, int prot, int flags, int fildes, off_t	offset);

       The  explain_message_mmap  function is used to obtain an	explanation of
       an error	returned by the	mmap(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.

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

       data_size
	       The original data_size, exactly as passed to the	mmap(2)	system
	       call.

       prot    The original prot, exactly as  passed  to  the  mmap(2)	system
	       call.

       flags   The  original  flags,  exactly  as passed to the	mmap(2)	system
	       call.

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

       offset  The  original  offset,  exactly as passed to the	mmap(2)	system
	       call.

       Example:	This function is intended to be	used in	a fashion  similar  to
       the following example:
	      void *result = mmap(data,	data_size, prot, flags,	fildes,	off-
	      set);
	      if (!result)
	      {
		  char message[3000];
		  explain_message_mmap(message,	sizeof(message), data,
		  data_size, prot, flags, fildes, offset);
		  fprintf(stderr, "%s\n", message);
		  exit(EXIT_FAILURE);
	      }

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

   explain_message_errno_mmap
       void explain_message_errno_mmap(char *message, int message_size,	int
       errnum, void *data, size_t data_size, int prot, int flags, int fildes,
       off_t offset);

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

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

       data_size
	       The original data_size, exactly as passed to the	mmap(2)	system
	       call.

       prot    The original prot, exactly as  passed  to  the  mmap(2)	system
	       call.

       flags   The  original  flags,  exactly  as passed to the	mmap(2)	system
	       call.

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

       offset  The  original  offset,  exactly as passed to the	mmap(2)	system
	       call.

       Example:	This function is intended to be	used in	a fashion  similar  to
       the following example:
	      void *result = mmap(data,	data_size, prot, flags,	fildes,	off-
	      set);
	      if (!result)
	      {
		  int err = errno;
		  char message[3000];
		  explain_message_errno_mmap(message, sizeof(message), err,
		  data,	data_size, prot, flags,	fildes,	offset);
		  fprintf(stderr, "%s\n", message);
		  exit(EXIT_FAILURE);
	      }

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

SEE ALSO
       mmap(2) map file	or device into memory

       explain_mmap_or_die(3)
	       map file	or device into memory and report errors

COPYRIGHT
       libexplain version 1.3
       Copyright (C) 2010 Peter	Miller

							       explain_mmap(3)

NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | COPYRIGHT

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