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explain_shmat(3)	   Library Functions Manual	      explain_shmat(3)

NAME
       explain_shmat - explain shmat(2)	errors

SYNOPSIS
       #include	<libexplain/shmat.h>
       const char *explain_shmat(int shmid, const void *shmaddr, int shmflg);
       const char *explain_errno_shmat(int errnum, int shmid, const void
       *shmaddr, int shmflg);
       void explain_message_shmat(char *message, int message_size, int shmid,
       const void *shmaddr, int	shmflg);
       void explain_message_errno_shmat(char *message, int message_size, int
       errnum, int shmid, const	void *shmaddr, int shmflg);

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

   explain_shmat
       const char *explain_shmat(int shmid, const void *shmaddr, int shmflg);

       The explain_shmat function is used to obtain an explanation of an error
       returned	by the shmat(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.

       shmid   The  original  shmid,  exactly as passed	to the shmat(2)	system
	       call.

       shmaddr The original shmaddr, exactly as	passed to the shmat(2)	system
	       call.

       shmflg  The  original  shmflg, exactly as passed	to the shmat(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 = shmat(shmid, shmaddr, shmflg);
	      if (!result)
	      {
		  fprintf(stderr, "%s\n", explain_shmat(shmid, shmaddr,	shm-
		  flg));
		  exit(EXIT_FAILURE);
	      }

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

   explain_errno_shmat
       const char *explain_errno_shmat(int errnum, int shmid, const void
       *shmaddr, int shmflg);

       The explain_errno_shmat function	is used	to obtain an explanation of an
       error returned by the shmat(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.

       shmid   The original shmid, exactly as passed to	 the  shmat(2)	system
	       call.

       shmaddr The  original shmaddr, exactly as passed	to the shmat(2)	system
	       call.

       shmflg  The original shmflg, exactly as passed to the  shmat(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 = shmat(shmid, shmaddr, shmflg);
	      if (!result)
	      {
		  int err = errno;
		  fprintf(stderr, "%s\n", explain_errno_shmat(err, shmid,
		  shmaddr, shmflg));
		  exit(EXIT_FAILURE);
	      }

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

   explain_message_shmat
       void explain_message_shmat(char *message, int message_size, int shmid,
       const void *shmaddr, int	shmflg);

       The explain_message_shmat function is used to obtain an explanation  of
       an  error  returned  by the shmat(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.

       shmid   The  original  shmid,  exactly as passed	to the shmat(2)	system
	       call.

       shmaddr The original shmaddr, exactly as	passed to the shmat(2)	system
	       call.

       shmflg  The  original  shmflg, exactly as passed	to the shmat(2)	system
	       call.

       Example:	This function is intended to be	used in	a fashion  similar  to
       the following example:
	      void *result = shmat(shmid, shmaddr, shmflg);
	      if (!result)
	      {
		  char message[3000];
		  explain_message_shmat(message, sizeof(message), shmid,
		  shmaddr, shmflg);
		  fprintf(stderr, "%s\n", message);
		  exit(EXIT_FAILURE);
	      }

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

   explain_message_errno_shmat
       void explain_message_errno_shmat(char *message, int message_size, int
       errnum, int shmid, const	void *shmaddr, int shmflg);

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

       shmid   The original shmid, exactly as passed to	 the  shmat(2)	system
	       call.

       shmaddr The  original shmaddr, exactly as passed	to the shmat(2)	system
	       call.

       shmflg  The original shmflg, exactly as passed to the  shmat(2)	system
	       call.

       Example:	 This  function	is intended to be used in a fashion similar to
       the following example:
	      void *result = shmat(shmid, shmaddr, shmflg);
	      if (!result)
	      {
		  int err = errno;
		  char message[3000];
		  explain_message_errno_shmat(message, sizeof(message),	err,
		  shmid, shmaddr, shmflg);
		  fprintf(stderr, "%s\n", message);
		  exit(EXIT_FAILURE);
	      }

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

SEE ALSO
       shmat(2)
	       shared memory attach

       explain_shmat_or_die(3)
	       shared memory attach and	report errors

COPYRIGHT
       libexplain version 1.3
       Copyright (C) 2011 Peter	Miller

							      explain_shmat(3)

NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | COPYRIGHT

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