GNU.WIKI: The GNU/Linux Knowledge Base

  [HOME] [PHP Manual] [HowTo] [ABS] [MAN1] [MAN2] [MAN3] [MAN4] [MAN5] [MAN6] [MAN7] [MAN8] [MAN9]

  [0-9] [Aa] [Bb] [Cc] [Dd] [Ee] [Ff] [Gg] [Hh] [Ii] [Jj] [Kk] [Ll] [Mm] [Nn] [Oo] [Pp] [Qq] [Rr] [Ss] [Tt] [Uu] [Vv] [Ww] [Xx] [Yy] [Zz]


NAME

       explain_fcntl - explain fcntl(2) errors

SYNOPSIS

       #include <libexplain/fcntl.h>
       const char *explain_fcntl(int fildes, int command, long arg);
       const  char  *explain_errno_fcntl(int  errnum, int fildes, int command,
       long arg);
       void explain_message_fcntl(char *message, int message_size, int fildes,
       int command, long arg);
       void  explain_message_errno_fcntl(char  *message, int message_size, int
       errnum, int fildes, int command, long arg);

DESCRIPTION

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

   explain_fcntl
       const char *explain_fcntl(int fildes, int command, long arg);

       The explain_fcntl function is used to obtain an explanation of an error
       returned by the fcntl(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.

       This  function  is  intended  to  be  used  in a fashion similar to the
       following example:
              if (fcntl(fildes, command, arg) < 0)
              {
                  fprintf(stderr, "%s
", explain_fcntl(fildes, command, arg));
                  exit(EXIT_FAILURE);
              }

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

       command The  original command, exactly as passed to the fcntl(2) system
               call.

       arg     The original arg, exactly as  passed  to  the  fcntl(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.

   explain_errno_fcntl
       const char *explain_errno_fcntl(int errnum, int  fildes,  int  command,
       long arg);

       The explain_errno_fcntl function is used to obtain an explanation of an
       error returned by the fcntl(2) system call.  The least the message will
       contain  is  the value of strerror(errnum), but usually it will do much
       better, and indicate the underlying cause in more detail.

       This function is intended to be  used  in  a  fashion  similar  to  the
       following example:
              if (fcntl(fildes, command, arg) < 0)
              {
                  int err = errno;
                  fprintf(stderr, "%s
", explain_errno_fcntl(err, fildes, command, arg));
                  exit(EXIT_FAILURE);
              }

       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 fcntl(2) system
               call.

       command The original command, exactly as passed to the fcntl(2)  system
               call.

       arg     The  original  arg,  exactly  as  passed to the fcntl(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.

   explain_message_fcntl
       void explain_message_fcntl(char *message, int message_size, int fildes,
       int command, long arg);

       The  explain_message_fcntl  function  may  be  used   to    obtain   an
       explanation  of  an  error  returned  by the fcntl(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.

       This  function  is  intended  to  be  used  in a fashion similar to the
       following example:
              if (fcntl(fildes, command, arg) < 0)
              {
                  char message[3000];
                  explain_message_fcntl(message, sizeof(message), fildes, command, arg);
                  fprintf(stderr, "%s
", message);
                  exit(EXIT_FAILURE);
              }

       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.

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

       command The original command, exactly as passed to the fcntl(2)  system
               call.

       arg     The  original  arg,  exactly  as  passed to the fcntl(2) system
               call.

   explain_message_errno_fcntl
       void explain_message_errno_fcntl(char *message, int  message_size,  int
       errnum, int fildes, int command, long arg);

       The  explain_message_errno_fcntl  function  may  be  used  to obtain an
       explanation of an error returned by  the  fcntl(2)  system  call.   The
       least  the  message  will contain is the value of strerror(errnum), but
       usually it will do much better, and indicate the  underlying  cause  in
       more detail.

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

       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.

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

       command The original command, exactly as passed to the fcntl(2)  system
               call.

       arg     The  original  arg,  exactly  as  passed to the fcntl(2) system
               call.

SEE ALSO

       fcntl(2)
               manipulate a file descriptor

       explain_fcntl_or_die(3)
               manipulate a file descriptor and report errors

COPYRIGHT

       libexplain version 0.52
       Copyright (C) 2008 Peter Miller

                                                              explain_fcntl(3)



  All copyrights belong to their respective owners. Other content (c) 2014-2018, GNU.WIKI. Please report site errors to webmaster@gnu.wiki.
Page load time: 0.160 seconds. Last modified: November 04 2018 12:49:43.