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explain_pipe2(3)	   Library Functions Manual	      explain_pipe2(3)

NAME
       explain_pipe2 - explain pipe2(2)	errors

SYNOPSIS
       #include	<libexplain/pipe2.h>
       const char *explain_pipe2(int *fildes, int flags);
       const char *explain_errno_pipe2(int errnum, int *fildes,	int flags);
       void explain_message_pipe2(char *message, int message_size, int
       *fildes,	int flags);
       void explain_message_errno_pipe2(char *message, int message_size, int
       errnum, int *fildes, int	flags);

DESCRIPTION
       These  functions	may be used to obtain explanations for errors returned
       by the pipe2(2) system call.

   explain_pipe2
       const char *explain_pipe2(int *fildes, int flags);

       The explain_pipe2 function is used to obtain an explanation of an error
       returned	 by  the pipe2(2) system call. The least the message will con-
       tain 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
       decoded.

       fildes  The original fildes, exactly as passed to the  pipe2(2)	system
	       call.

       flags   The  original  flags,  exactly as passed	to the pipe2(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 (pipe2(fildes,	flags) < 0)
	      {
		  fprintf(stderr, "%s\n", explain_pipe2(fildes,	flags));
		  exit(EXIT_FAILURE);
	      }

       The  above  code	 example  is  available	 pre-packaged	as   the   ex-
       plain_pipe2_or_die(3) function.

   explain_errno_pipe2
       const char *explain_errno_pipe2(int errnum, int *fildes,	int flags);

       The explain_errno_pipe2 function	is used	to obtain an explanation of an
       error returned by the pipe2(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  pipe2(2)	system
	       call.

       flags   The  original  flags,  exactly as passed	to the pipe2(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 (pipe2(fildes,	flags) < 0)
	      {
		  int err = errno;
		  fprintf(stderr, "%s\n", explain_errno_pipe2(err, fildes,
		  flags));
		  exit(EXIT_FAILURE);
	      }

       The   above   code   example  is	 available  pre-packaged  as  the  ex-
       plain_pipe2_or_die(3) function.

   explain_message_pipe2
       void explain_message_pipe2(char *message, int message_size, int
       *fildes,	int flags);

       The  explain_message_pipe2 function is used to obtain an	explanation of
       an error	returned by the	pipe2(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  pipe2(2)	system
	       call.

       flags   The  original  flags,  exactly as passed	to the pipe2(2)	system
	       call.

       Example:	This function is intended to be	used in	a fashion  similar  to
       the following example:
	      if (pipe2(fildes,	flags) < 0)
	      {
		  char message[3000];
		  explain_message_pipe2(message, sizeof(message), fildes,
		  flags);
		  fprintf(stderr, "%s\n", message);
		  exit(EXIT_FAILURE);
	      }

       The  above  code	 example  is  available	 pre-packaged	as   the   ex-
       plain_pipe2_or_die(3) function.

   explain_message_errno_pipe2
       void explain_message_errno_pipe2(char *message, int message_size, int
       errnum, int *fildes, int	flags);

       The explain_message_errno_pipe2 function	is used	to obtain an  explana-
       tion  of	 an  error returned by the pipe2(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  pipe2(2)	system
	       call.

       flags   The  original  flags,  exactly as passed	to the pipe2(2)	system
	       call.

       Example:	This function is intended to be	used in	a fashion  similar  to
       the following example:
	      if (pipe2(fildes,	flags) < 0)
	      {
		  int err = errno;
		  char message[3000];
		  explain_message_errno_pipe2(message, sizeof(message),	err,
		  fildes, flags);
		  fprintf(stderr, "%s\n", message);
		  exit(EXIT_FAILURE);
	      }

       The  above  code	 example  is  available	 pre-packaged	as   the   ex-
       plain_pipe2_or_die(3) function.

SEE ALSO
       pipe2(2)
	       create pipe

       explain_pipe2_or_die(3)
	       create pipe and report errors

COPYRIGHT
       libexplain version 1.3
       Copyright (C) 2013 Peter	Miller

							      explain_pipe2(3)

NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | COPYRIGHT

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