explain_getpeername(3)

💖 explain_getpeername 💖

okay bestie, gather round, because we're talking about explain_getpeername(3) — it lives in the Library Functions Manual and it's literally here to explain getpeername(2) errors to you like a bestie who actually knows what's going on ✨

---

🌸 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 🦋

So these functions? They're your little helpers for getting explanations when the getpeername(2) system call returns an error. Like, instead of just staring at a cryptic errno going "what does that even mean 😭", you call one of these and it tells you. Iconic behaviour, honestly.

✨ explain_getpeername ✨

const char *explain_getpeername(int fildes, struct sockaddr *sock_addr,
socklen_t *sock_addr_size);

The explain_getpeername function gets you 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 goes way harder than that and tells you the underlying cause in more detail. it's giving ✨thorough✨.

The errno global variable will be used to obtain the error value to be decoded.

This function is meant 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. (convenience? she has it 💅)

• 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. It will be overwritten by the next call to any libexplain function which shares this buffer, including other threads. so like, don't get attached to it bestie, it's not yours 👑

Note: This function is not thread safe, because it shares a return buffer across all threads, and many other functions in this library. no cap.

🌈 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 gets you 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 does much better and indicates the underlying cause in more detail. obsessed with the detail tbh.

This function is meant 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. (rude of them, honestly.)
• 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 does much better, and indicates the underlying cause in more detail.

The errno global variable will be used to obtain the error value to be decoded.

This function is meant 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. (she said "I brought my own buffer" and honestly? queen.)
• 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 does much better, and indicates the underlying cause in more detail.

This function is meant 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

---

okay that's the whole page bestie, you're literally so welcome 💖 this was explain_getpeername(3) from the Library Functions Manual, libexplain version 1.4, © 2009 Peter Miller — go forth and debug your sockets, you absolute main character 🦋✨ periodt.