explain_socketpair(3)

NAME
explain_socketpair - explain socketpair(2) errors

SYNOPSIS
#include <libexplain/socketpair.h>

const char *explain_socketpair(int domain, int type, int protocol, int *sv);
const char *explain_errno_socketpair(int errnum, int domain, int type, int protocol, int *sv);
void explain_message_socketpair(char *message, int message_size, int domain, int type, int protocol, int *sv);
void explain_message_errno_socketpair(char *message, int message_size, int errnum, int domain, int type, int protocol, int *sv);

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

  explain_socketpair
const char *explain_socketpair(int domain, int type, int protocol, int *sv);

The explain_socketpair function is used to obtain an explanation of an error returned by the socketpair(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.

domain
    The original domain, exactly as passed to the socketpair(2) system call.

type
    The original type, exactly as passed to the socketpair(2) system call.

protocol
    The original protocol, exactly as passed to the socketpair(2) system call.

sv  The original sv, exactly as passed to the socketpair(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:
    if (socketpair(domain, type, protocol, sv) < 0)
    {
    fprintf(stderr, "%s\n", explain_socketpair(domain, type, protocol, sv));
        exit(EXIT_FAILURE);
    }

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

  explain_errno_socketpair
const char *explain_errno_socketpair(int errnum, int domain, int type, int protocol, int *sv);

The explain_errno_socketpair function is used to obtain an explanation of an error returned by the socketpair(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.

domain
    The original domain, exactly as passed to the socketpair(2) system call.

type
    The original type, exactly as passed to the socketpair(2) system call.

protocol
    The original protocol, exactly as passed to the socketpair(2) system call.

sv  The original sv, exactly as passed to the socketpair(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:
    if (socketpair(domain, type, protocol, sv) < 0)
    {
        int err = errno;
    fprintf(stderr, "%s\n", explain_errno_socketpair(err, domain, type, protocol, sv));
        exit(EXIT_FAILURE);
    }

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

  explain_message_socketpair
void explain_message_socketpair(char *message, int message_size, int domain, int type, int protocol, int *sv);

The explain_message_socketpair function is used to obtain an explanation of an error returned by the socketpair(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.

domain
    The original domain, exactly as passed to the socketpair(2) system call.

type
    The original type, exactly as passed to the socketpair(2) system call.

protocol
    The original protocol, exactly as passed to the socketpair(2) system call.

sv  The original sv, exactly as passed to the socketpair(2) system call.

Example: This function is intended to be used in a fashion similar to the following example:
    if (socketpair(domain, type, protocol, sv) < 0)
    {
        char message[3000];
    explain_message_socketpair(message, sizeof(message), domain, type, protocol, sv);
        fprintf(stderr, "%s\n", message);
        exit(EXIT_FAILURE);
    }

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

  explain_message_errno_socketpair
void explain_message_errno_socketpair(char *message, int message_size, int errnum, int domain, int type, int protocol, int *sv);

The explain_message_errno_socketpair function is used to obtain an explanation of an error returned by the socketpair(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.

domain
    The original domain, exactly as passed to the socketpair(2) system call.

type
    The original type, exactly as passed to the socketpair(2) system call.

protocol
    The original protocol, exactly as passed to the socketpair(2) system call.

sv  The original sv, exactly as passed to the socketpair(2) system call.

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

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

SEE ALSO

socketpair(2)
    create a pair of connected sockets

explain_socketpair_or_die(3)
    create a pair of connected sockets and report errors

COPYRIGHT
libexplain version
Copyright (C) 2010 Peter Miller