explain_readlink(3)

💖 explain_readlink(3) 💖

okay bestie, listen up — this is a page from the Library Functions Manual, and it's literally about explaining your readlink(2) errors. no cap, it's giving "the compiler is nicer than your ex" energy. let's go 🦋

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✨ NAME ✨

explain_readlink — explain readlink(2) errors 🫶

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🌸 SYNOPSIS 🌸

#include <libexplain/readlink.h>
const char *explain_readlink(const char *pathname, char *data, size_t
data_size);
const char *explain_errno_readlink(int errnum, const char *pathname,
char *data, size_t data_size);
void explain_message_readlink(char *message, int message_size, const
char *pathname, char *data, size_t data_size);
void explain_message_errno_readlink(char *message, int message_size, int
errnum, const char *pathname, char *data, size_t data_size);

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👑 DESCRIPTION 👑

These functions may be used to obtain explanations for errors returned by the readlink(2) system call. so when the syscall goes 💀, these are the besties you call.

🌈 explain_readlink

const char *explain_readlink(const char *pathname, char *data, size_t
data_size);

The explain_readlink function is used to obtain an explanation of an error returned by the readlink(2) system call. The least the message will contain is the value of strerror(errno) — but usually it does so much better and tells you the actual underlying cause in more detail. it's giving detective energy 🔍

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:

if (readlink(pathname, data, data_size) < 0)
{
    fprintf(stderr, "%s\n", explain_readlink(pathname, data, data_size));
    exit(EXIT_FAILURE);
}

• pathname — the original pathname, exactly as passed to the readlink(2) system call. yes bestie, exactly, don't be out here editing it 💅
• data — the original data, exactly as passed to the readlink(2) system call.
• data_size — the original data_size, exactly as passed to the readlink(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. so like… it's a communal whiteboard, don't get attached 😭

Note: This function is not thread safe, because it shares a return buffer across all threads, and many other functions in this library. periodt. ⚠️

🦋 explain_errno_readlink

const char *explain_errno_readlink(int errnum, const char *pathname,
char *data, size_t data_size);

The explain_errno_readlink function is used to obtain an explanation of an error returned by the readlink(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. main character explanation behavior, honestly ✨

This function is intended to be used in a fashion similar to the following example:

if (readlink(pathname, data, data_size) < 0)
{
    int err = errno;
    fprintf(stderr, "%s\n", explain_errno_readlink(err, pathname, data,
        data_size));
    exit(EXIT_FAILURE);
}

• 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. like bestie, errno is feral, it changes the second you look away 🙈
• pathname — the original pathname, exactly as passed to the readlink(2) system call.
• data — the original data, exactly as passed to the readlink(2) system call.
• data_size — the original data_size, exactly as passed to the readlink(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_readlink

void explain_message_readlink(char *message, int message_size, const
char *pathname, char *data, size_t data_size);

The explain_message_readlink function may be used to obtain an explanation of an error returned by the readlink(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. it's the "bring your own buffer" version, so it's lowkey the responsible one 🫶

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:

if (readlink(pathname, data, data_size) < 0)
{
    char message[3000];
    explain_message_readlink(message, sizeof(message), pathname, data,
        data_size);
    fprintf(stderr, "%s\n", message);
    exit(EXIT_FAILURE);
}

• message — the location in which to store the returned message. If a suitable message return buffer is supplied, this function is thread safe. slay 💅
• message_size — the size in bytes of the location in which to store the returned message.
• pathname — the original pathname, exactly as passed to the readlink(2) system call.
• data — the original data, exactly as passed to the readlink(2) system call.
• data_size — the original data_size, exactly as passed to the readlink(2) system call.

🧚 explain_message_errno_readlink

void explain_message_errno_readlink(char *message, int message_size, int
errnum, const char *pathname, char *data, size_t data_size);

The explain_message_errno_readlink function may be used to obtain an explanation of an error returned by the readlink(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 is the final boss combo: your own buffer and your own errnum 🔥

This function is intended to be used in a fashion similar to the following example:

if (readlink(pathname, data, data_size) < 0)
{
    int err = errno;
    char message[3000];
    explain_message_errno_readlink(message, sizeof(message), err, pathname,
        data, data_size);
    fprintf(stderr, "%s\n", message);
    exit(EXIT_FAILURE);
}

• 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.
• pathname — the original pathname, exactly as passed to the readlink(2) system call.
• data — the original data, exactly as passed to the readlink(2) system call.
• data_size — the original data_size, exactly as passed to the readlink(2) system call.

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💜 SEE ALSO 💜

• readlink(2) — blah blah blah
• explain_readlink_or_die(3) — blah blah blah and report errors

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🌟 COPYRIGHT 🌟

libexplain version 1.4 Copyright (C) 2008 Peter Miller

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and that's the whole page, bestie 💖 go forth, catch those errors, explain them iconically. this was the explain_readlink(3) page from the Library Functions Manual, libexplain version 1.4, copyright (C) 2008 Peter Miller — mwah, take care of her 🎀✨💅