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explain_setpriority(3)	   Library Functions Manual	explain_setpriority(3)

NAME
       explain_setpriority - explain setpriority(2) errors

SYNOPSIS
       #include	<libexplain/setpriority.h>
       const char *explain_setpriority(int which, int who, int prio);
       const char *explain_errno_setpriority(int errnum, int which, int	who,
       int prio);
       void explain_message_setpriority(char *message, int message_size, int
       which, int who, int prio);
       void explain_message_errno_setpriority(char *message, int message_size,
       int errnum, int which, int who, int prio);

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

   explain_setpriority
       const char *explain_setpriority(int which, int who, int prio);

       The explain_setpriority function	is used	to obtain an explanation of an
       error returned by the setpriority(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.

       which   The  original  which,  exactly  as passed to the	setpriority(2)
	       system call.

       who     The original who, exactly as passed to the setpriority(2)  sys-
	       tem call.

       prio    The original prio, exactly as passed to the setpriority(2) sys-
	       tem 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 (setpriority(which, who, prio)	< 0)
	      {
		  fprintf(stderr, "%s\n", explain_setpriority(which, who,
		  prio));
		  exit(EXIT_FAILURE);
	      }

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

   explain_errno_setpriority
       const char *explain_errno_setpriority(int errnum, int which, int	who,
       int prio);

       The explain_errno_setpriority function is used to obtain	an explanation
       of an error returned by the setpriority(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.

       which   The original which, exactly as  passed  to  the	setpriority(2)
	       system call.

       who     The  original who, exactly as passed to the setpriority(2) sys-
	       tem call.

       prio    The original prio, exactly as passed to the setpriority(2) sys-
	       tem 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 (setpriority(which, who, prio)	< 0)
	      {
		  int err = errno;
		  fprintf(stderr, "%s\n", explain_errno_setpriority(err,
		  which, who, prio));
		  exit(EXIT_FAILURE);
	      }

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

   explain_message_setpriority
       void explain_message_setpriority(char *message, int message_size, int
       which, int who, int prio);

       The explain_message_setpriority function	is used	to obtain an  explana-
       tion of an error	returned by the	setpriority(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 de-
       tail.

       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.

       which   The original which, exactly as  passed  to  the	setpriority(2)
	       system call.

       who     The  original who, exactly as passed to the setpriority(2) sys-
	       tem call.

       prio    The original prio, exactly as passed to the setpriority(2) sys-
	       tem call.

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

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

   explain_message_errno_setpriority
       void explain_message_errno_setpriority(char *message, int message_size,
       int errnum, int which, int who, int prio);

       The explain_message_errno_setpriority function is used to obtain	an ex-
       planation of an error returned by the setpriority(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.

       which   The original which, exactly as  passed  to  the	setpriority(2)
	       system call.

       who     The  original who, exactly as passed to the setpriority(2) sys-
	       tem call.

       prio    The original prio, exactly as passed to the setpriority(2) sys-
	       tem call.

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

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

SEE ALSO
       setpriority(2)
	       set program scheduling priority

       explain_setpriority_or_die(3)
	       set program scheduling priority and report errors

COPYRIGHT
       libexplain version 1.3
       Copyright (C) 2013 Peter	Miller

							explain_setpriority(3)

NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | COPYRIGHT

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