Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages

  
 
  

home | help
explain_access(3)	   Library Functions Manual	     explain_access(3)

NAME
       explain_access -	explain	access(2) errors

SYNOPSIS
       #include	<libexplain/access.h>
       const char *explain_access(const	char *pathname,	int mode);
       const  char *explain_errno_access(int errnum, const char	*pathname, int
       mode);
       void explain_message_access(char	*message, int message_size, const char
       *pathname, int mode);
       void  explain_message_errno_access(char *message, int message_size, int
       errnum, const char *pathname, int mode);

DESCRIPTION
       These functions may be used to obtain explanations  for	access(2)  er-
       rors.

   explain_access
       const char *explain_access(const	char *pathname,	int mode);

       The  explain_access function is used to obtain an explanation of	an er-
       ror returned by the access(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 fol-
       lowing example:
	      int fd = access(pathname,	mode);
	      if (fd < 0)
	      {
		  fprintf(stderr, "%s0,	explain_access(pathname, mode));
		  exit(EXIT_FAILURE);
	      }

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

       mode    The  original  mode,  exactly as	passed to the access(2)	system
	       call.  TP 8n 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 over-
	       written	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.

   explain_errno_access
       const  char *explain_errno_access(int errnum, const char	*pathname, int
       mode);

       The explain_errno_access	function is used to obtain an  explanation  of
       an  error returned by the access(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 fol-
       lowing example:
	      int fd = access(pathname,	mode);
	      if (fd < 0)
	      {
		  int err = errno;
		  fprintf(stderr, "%s0,	explain_errno_access(err, pathname,
		      mode));
		  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.

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

       mode    The  original  mode,  exactly as	passed to the access(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, in-
	       cluding 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.

   explain_message_access
       void explain_message_access(char	*message, int message_size, const char
       *pathname, int mode);

       The explain_message_access function is used to obtain an	explanation of
       an  error returned by the access(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  fol-
       lowing example:
	      int fd = access(pathname,	mode);
	      if (fd < 0)
	      {
		  char message[3000];
		  explain_message_access(message, sizeof(message), pathname,
		      mode);
		  fprintf(stderr, "%s0,	message);
		  exit(EXIT_FAILURE);
	      }

       message The location in which to	store the returned message.  Because a
	       message return buffer  has  been	 supplied,  this  function  is
	       thread safe.

       message_size
	       The  size  in  bytes  of	the location in	which to store the re-
	       turned message.

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

       mode    The  original  mode,  exactly as	passed to the access(2)	system
	       call.

   explain_message_errno_access
       void explain_message_errno_access(char *message,	int message_size,  int
       errnum, const char *pathname, int mode);

       The explain_message_errno_access	function is used to obtain an explana-
       tion of an error	returned by the	access(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  fol-
       lowing exameple:
	      int fd = access(pathname,	mode);
	      if (fd < 0)
	      {
		  int err = errno;
		  char message[3000];
		  explain_message_errno_access(message,	sizeof(message), err,
		      pathname,	mode);
		  fprintf(stderr, "%s0,	message);
		  exit(EXIT_FAILURE);
	      }

       message The location in which to	store the returned message.  Because a
	       message return buffer  has  been	 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.

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

       mode    The  original  mode,  exactly as	passed to the access(2)	system
	       call.

COPYRIGHT
       libexplain version 1.3
       Copyright (C) 2008 Peter	Miller

AUTHOR
       Written by Peter	Miller <pmiller@opensource.org.au>

							     explain_access(3)

NAME | SYNOPSIS | DESCRIPTION | COPYRIGHT | AUTHOR

Want to link to this manual page? Use this URL:
<https://www.freebsd.org/cgi/man.cgi?query=explain_access&sektion=3&manpath=FreeBSD+12.2-RELEASE+and+Ports>

home | help