Provided by: libexplain-dev_1.4.D001-12_amd64 
NAME
explain_getpeername - explain getpeername(2) errors
SYNOPSIS
#include <libexplain/getpeername.h>
const char *explain_getpeername(int fildes, struct sockaddr *sock_addr, socklen_t
*sock_addr_size);
const char *explain_errno_getpeername(int errnum, int fildes, struct sockaddr *sock_addr,
socklen_t *sock_addr_size);
void explain_message_getpeername(char *message, int message_size, int fildes, struct
sockaddr *sock_addr, socklen_t *sock_addr_size);
void explain_message_errno_getpeername(char *message, int message_size, int errnum, int
fildes, struct sockaddr *sock_addr, socklen_t *sock_addr_size);
DESCRIPTION
These functions may be used to obtain explanations for errors returned by the
getpeername(2) system call.
explain_getpeername
const char *explain_getpeername(int fildes, struct sockaddr *sock_addr, socklen_t
*sock_addr_size);
The explain_getpeername function is used to obtain an explanation of an error returned by
the getpeername(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:
struct sockaddr sock_addr;
socklen_t sock_addr_len = sizeof(sock_addr);
if (getpeername(fildes, &sock_addr, &sock_addr_size) < 0)
{
fprintf(stderr, "%s\n", explain_getpeername(fildes,
&sock_addr, &sock_addr_size));
exit(EXIT_FAILURE);
}
The above code example is available pre‐packaged as the explain_getpeername_or_die(3)
function.
fildes The original fildes, exactly as passed to the getpeername(2) system call.
sock_addr
The original sock_addr, exactly as passed to the getpeername(2) system call.
sock_addr_size
The original sock_addr_size, exactly as passed to the getpeername(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_getpeername
const char *explain_errno_getpeername(int errnum, int fildes, struct sockaddr *sock_addr,
socklen_t *sock_addr_size);
The explain_errno_getpeername function is used to obtain an explanation of an error
returned by the getpeername(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:
struct sockaddr sock_addr;
socklen_t sock_addr_len = sizeof(sock_addr);
if (getpeername(fildes, &sock_addr, &sock_addr_size) < 0)
{
int err = errno;
fprintf(stderr, "%s\n", explain_errno_getpeername(err,
fildes, &sock_addr, &sock_addr_size));
exit(EXIT_FAILURE);
}
The above code example is available pre‐packaged as the explain_getpeername_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 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 getpeername(2) system call.
sock_addr
The original sock_addr, exactly as passed to the getpeername(2) system call.
sock_addr_size
The original sock_addr_size, exactly as passed to the getpeername(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_getpeername
void explain_message_getpeername(char *message, int message_size, int fildes, struct
sockaddr *sock_addr, socklen_t *sock_addr_size);
The explain_message_getpeername function may be used to obtain an explanation of an error
returned by the getpeername(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:
struct sockaddr sock_addr;
socklen_t sock_addr_len = sizeof(sock_addr);
if (getpeername(fildes, &sock_addr, &sock_addr_size) < 0)
{
char message[3000];
explain_message_getpeername(message, sizeof(message),
fildes, &sock_addr, &sock_addr_size);
fprintf(stderr, "%s\n", message);
exit(EXIT_FAILURE);
}
The above code example is available pre‐packaged as the explain_getpeername_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.
fildes The original fildes, exactly as passed to the getpeername(2) system call.
sock_addr
The original sock_addr, exactly as passed to the getpeername(2) system call.
sock_addr_size
The original sock_addr_size, exactly as passed to the getpeername(2) system call.
explain_message_errno_getpeername
void explain_message_errno_getpeername(char *message, int message_size, int errnum, int
fildes, struct sockaddr *sock_addr, socklen_t *sock_addr_size);
The explain_message_errno_getpeername function may be used to obtain an explanation of an
error returned by the getpeername(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:
struct sockaddr sock_addr;
socklen_t sock_addr_len = sizeof(sock_addr);
if (getpeername(fildes, &sock_addr, &sock_addr_size) < 0)
{
int err = errno;
char message[3000];
explain_message_errno_getpeername(message, sizeof(message),
err, fildes, &sock_addr, &sock_addr_size);
fprintf(stderr, "%s\n", message);
exit(EXIT_FAILURE);
}
The above code example is available pre‐packaged as the explain_getpeername_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 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 getpeername(2) system call.
sock_addr
The original sock_addr, exactly as passed to the getpeername(2) system call.
sock_addr_size
The original sock_addr_size, exactly as passed to the getpeername(2) system call.
SEE ALSO
getpeername(2)
get name of connected peer socket
explain_getpeername_or_die(3)
get name of connected peer socket and report errors
COPYRIGHT
libexplain version 1.4
Copyright (C) 2009 Peter Miller
explain_getpeername(3)