Provided by: libexplain-dev_1.4.D001-8_amd64 bug

NAME

       explain_getpriority - explain getpriority(2) errors

SYNOPSIS

       #include <libexplain/getpriority.h>
       const char *explain_getpriority(int which, int who);
       const char *explain_errno_getpriority(int errnum, int which, int who);
       void explain_message_getpriority(char *message, int message_size, int which, int who);
       void explain_message_errno_getpriority(char *message, int message_size, int errnum, int
       which, int who);

DESCRIPTION

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

   explain_getpriority
       const char *explain_getpriority(int which, int who);

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

       who     The original who, exactly as passed to the getpriority(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 buffer 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:
              int result = getpriority(which, who);
              if (result < 0)
              {
                  fprintf(stderr, "%s\n", explain_getpriority(which, who));
                  exit(EXIT_FAILURE);
              }

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

   explain_errno_getpriority
       const char *explain_errno_getpriority(int errnum, int which, int who);

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

       who     The original who, exactly as passed to the getpriority(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 buffer 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:
              int result = getpriority(which, who);
              if (result < 0)
              {
                  int err = errno;
                  fprintf(stderr, "%s\n", explain_errno_getpriority(err, which, who));
                  exit(EXIT_FAILURE);
              }

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

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

       The explain_message_getpriority function is used to obtain  an  explanation  of  an  error
       returned  by  the  getpriority(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 suitable message return
               buffer is supplied, this function is thread safe.

       message_size
               The size in bytes of the location in which to store the returned message.

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

       who     The original who, exactly as passed to the getpriority(2) system call.

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

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

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

       The  explain_message_errno_getpriority  function  is  used  to obtain an explanation of an
       error returned by the getpriority(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 suitable message  return
               buffer is supplied, this function is thread safe.

       message_size
               The size in bytes of the location in which to store the returned 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 getpriority(2) system call.

       who     The original who, exactly as passed to the getpriority(2) system call.

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

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

SEE ALSO

       getpriority(2)
               get program scheduling priority

       explain_getpriority_or_die(3)
               get program scheduling priority and report errors

COPYRIGHT

       libexplain version 1.4
       Copyright (C) 2013 Peter Miller

                                                                           explain_getpriority(3)