explain_getsockname(3)

💖 explain_getsockname(3) — Library Functions Manual 💖

okay bestie, so this is the <pink>explain_getsockname</pink> page from the Library Functions Manual, and it's literally all about explaining the errors that getsockname(2) throws at you. it's giving "your syscall failed and here's why, in actual words." 🫶

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✨ NAME ✨

explain_getsockname — explain getsockname(2) errors

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🌸 SYNOPSIS 🌸

#include <libexplain/getsockname.h>

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

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

void explain_message_getsockname(char *message, int message_size, int fildes, struct sockaddr *sock_addr, socklen_t *sock_addr_size);

void explain_message_errno_getsockname(char *message, int message_size, int errnum, int fildes, struct sockaddr *sock_addr, socklen_t *sock_addr_size);

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🦋 DESCRIPTION 🦋

so these functions? they're your little helpers for getting explanations of errors that the getsockname(2) system call hands back. like, instead of a cryptic number, you get lore. 💅

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🌈 explain_getsockname

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

the explain_getsockname function gets you an explanation of an error returned by the getsockname(2) system call. the least the message will contain is the value of strerror(errno), but usually it does much better and points at the actual underlying cause in more detail. no cap. ✨

the errno global variable is the one used to get the error value that's gonna be decoded.

this function is meant to be used kinda like this:

struct sockaddr sock_addr;
socklen_t sock_addr_size = sizeof(sock_addr);
if (getsockname(fildes, &sock_addr, &sock_addr_size) < 0)
{
    fprintf(stderr, "%s\n", explain_getsockname(fildes,
        &sock_addr, &sock_addr_size));
    exit(EXIT_FAILURE);
}

the above code example is available pre-packaged as the explain_getsockname_or_die(3) function. obsessed. 🎀

• fildes — the original fildes, exactly as passed to the getsockname(2) system call.
• sock_addr — the original sock_addr, exactly as passed to the getsockname(2) system call.
• sock_addr_size — the original sock_addr_size, exactly as passed to the getsockname(2) system call.

Returns: the message explaining the error. this message buffer is shared by all libexplain functions that don't supply a buffer in their argument list. it gets overwritten by the next call to any libexplain function that shares this buffer — including from other threads. 😭

Note: this function is not thread safe, because it shares a return buffer across all threads, and so do many other functions in this library. bestie, do not rawdog this one from multiple threads. 💀

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🌟 explain_errno_getsockname

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

the explain_errno_getsockname function gets you an explanation of an error returned by the getsockname(2) system call. the least the message will contain is the value of strerror(errnum), but usually it does much better and tells you the underlying cause in more detail. 💖

this function is meant to be used kinda like this:

struct sockaddr sock_addr;
socklen_t sock_addr_size = sizeof(sock_addr);
if (getsockname(fildes, &sock_addr, &sock_addr_size) < 0)
{
    int err = errno;
    fprintf(stderr, "%s\n", explain_errno_getsockname(err,
        fildes, &sock_addr, &sock_addr_size));
    exit(EXIT_FAILURE);
}

the above code example is available pre-packaged as the explain_getsockname_or_die(3) function. iconic. ✨

• errnum — the error value to be decoded, usually grabbed from the errno global variable right before this function is called. this is necessary if you need to run any code between the system call being explained and this function, because lots of libc functions will mess with the value of errno.
• fildes — the original fildes, exactly as passed to the getsockname(2) system call.
• sock_addr — the original sock_addr, exactly as passed to the getsockname(2) system call.
• sock_addr_size — the original sock_addr_size, exactly as passed to the getsockname(2) system call.

Returns: the message explaining the error. this message buffer is shared by all libexplain functions that don't supply a buffer in their argument list. it gets overwritten by the next call to any libexplain function that shares this buffer — including from 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 do too. periodt.

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🧚 explain_message_getsockname

void explain_message_getsockname(char *message, int message_size, int fildes, struct sockaddr *sock_addr, socklen_t *sock_addr_size);

the explain_message_getsockname function may be used to obtain an explanation of an error returned by the getsockname(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 is used to obtain the error value to be decoded.

this function is meant to be used kinda like this:

struct sockaddr sock_addr;
socklen_t sock_addr_size = sizeof(sock_addr);
if (getsockname(fildes, &sock_addr, &sock_addr_size) < 0)
{
    char message[3000];
    explain_message_getsockname(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_getsockname_or_die(3) function. slay. 💅

• message — the location in which to store the returned message. if you supply a suitable message return buffer, 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 getsockname(2) system call.
• sock_addr — the original sock_addr, exactly as passed to the getsockname(2) system call.
• sock_addr_size — the original sock_addr_size, exactly as passed to the getsockname(2) system call.

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🍓 explain_message_errno_getsockname

void explain_message_errno_getsockname(char *message, int message_size, int errnum, int fildes, struct sockaddr *sock_addr, socklen_t *sock_addr_size);

the explain_message_errno_getsockname function may be used to obtain an explanation of an error returned by the getsockname(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 kinda like this:

struct sockaddr sock_addr;
socklen_t sock_addr_size = sizeof(sock_addr);
if (getsockname(fildes, &sock_addr, &sock_addr_size) < 0)
{
    int err = errno;
    char message[3000];
    explain_message_errno_getsockname(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_getsockname_or_die(3) function. ate. ✨

• message — the location in which to store the returned message. if you supply a suitable message return buffer, 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 right before this function is called. this is necessary if you need to call any code between the system call being explained and this function, because many libc functions will alter the value of errno.
• fildes — the original fildes, exactly as passed to the getsockname(2) system call.
• sock_addr — the original sock_addr, exactly as passed to the getsockname(2) system call.
• sock_addr_size — the original sock_addr_size, exactly as passed to the getsockname(2) system call.

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🌸 SEE ALSO 🌸

• getsockname(2) — get socket name
• explain_getsockname_or_die(3) — get socket name and report errors

iykyk, go read those next. 🦋

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💜 COPYRIGHT 💜

libexplain version 1.4 Copyright (C) 2009 Peter Miller

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okay that's the whole page bestie, you're officially a getsockname(2) error-decoding main character now 💅✨ — this was explain_getsockname(3), brought to you by the Library Functions Manual, libexplain version 1.4, Copyright (C) 2009 Peter Miller. go forth and explain those errors, queen 👑🎀