explain_getaddrinfo(3)					     Library Functions Manual					    explain_getaddrinfo(3)

NAME

       explain_getaddrinfo - explain getaddrinfo(3) errors

SYNOPSIS

       #include <libexplain/getaddrinfo.h>
       const  char  *explain_errcode_getaddrinfo(int  errnum, const char *node, const char *service, const struct addrinfo *hints, struct addrinfo
       **res);
       void explain_message_errcode_getaddrinfo(char *message, int message_size, int errnum, const char *node, const char *service,  const  struct
       addrinfo *hints, struct addrinfo **res);

DESCRIPTION

       These functions may be used to obtain explanations for errors returned by the getaddrinfo(3) system call.

   explain_errcode_getaddrinfo
       const  char  *explain_errcode_getaddrinfo(int  errnum, const char *node, const char *service, const struct addrinfo *hints, struct addrinfo
       **res);

       The explain_errcode_getaddrinfo function is used to obtain an explanation of an error returned by  the  getaddrinfo(3)  system  call.   The
       least the message will contain is the value of gai_strerror(errcode), 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:
	      int errcode = getaddrinfo(node, service, hints, res);
	      if (errncode == GAI_SYSTEM)
		  errcode = errno;
	      if (errcode)
	      {
		  fprintf(stderr, "%s
", explain_errcode_getaddrinfo(errcode,
		      node, service, hints, res));
		  exit(EXIT_FAILURE);
	      }

       The above code example is available as the explain_getaddrinfo_or_die(3) function.

       errnum  The error value to be decoded, usually obtained from the errno global variable just before this function is called.  This is neces-
	       sary 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.

       node    The original node, exactly as passed to the getaddrinfo(3) system call.

       service The original service, exactly as passed to the getaddrinfo(3) system call.

       hints   The original hints, exactly as passed to the getaddrinfo(3) system call.

       res     The original res, exactly as passed to the getaddrinfo(3) 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_errno_getaddrinfo
       void explain_message_errno_getaddrinfo(char *message, int message_size, int errnum, const char *node, const  char  *service,  const  struct
       addrinfo *hints, struct addrinfo **res);

       The explain_message_errno_getaddrinfo function may be used to obtain an explanation of an error returned by the getaddrinfo(3) 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:
	      int errcode = getaddrinfo(node, service, hints, res);
	      if (errnode == EAI_SYSTEM)
		  errcode = errno;
	      if (errcode)
	      {
		  char message[3000];
		  explain_message_errcode_getaddrinfo(message, sizeof(message),
		      errcode, node, service, hints, res);
		  fprintf(stderr, "%s
", message);
		  exit(EXIT_FAILURE);
	      }

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

       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 neces-
	       sary 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.

       node    The original node, exactly as passed to the getaddrinfo(3) system call.

       service The original service, exactly as passed to the getaddrinfo(3) system call.

       hints   The original hints, exactly as passed to the getaddrinfo(3) system call.

       res     The original res, exactly as passed to the getaddrinfo(3) system call.

SEE ALSO

       getaddrinfo(3)
	       network address and

       explain_getaddrinfo_or_die(3)
	       network address and and report errors

COPYRIGHT

       libexplain version 0.52
       Copyright (C) 2008 Peter Miller

															    explain_getaddrinfo(3)