explain_chdir(3)

✨ explain_chdir(3) ✨

okay bestie, gather round 💖 this is the explain_chdir page from libexplain's Library Functions Manual, and it's literally your little glow-up for chdir(2) error messages. no cap.

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🌸 NAME 🌸

explain_chdir — explain chdir(2) errors 🦋

like, it takes a cryptic errno situation and turns it into an actual sentence you can read. iconic behaviour tbh.

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✨ SYNOPSIS ✨

#include <libexplain/chdir.h>
const char *explain_chdir(const char *pathname);
void explain_message_chdir(char *message, int message_size, const char *pathname);
const char *explain_errno_chdir(int errnum, const char *pathname);
void explain_message_errno_chdir(char *message, int message_size, int errnum, const char *pathname);

four functions, one mission: tell you what actually went wrong 💅

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💜 DESCRIPTION 💜

These functions may be used to obtain explanations of chdir(2) errors. that's the whole vibe.

🎀 explain_chdir

const char *explain_chdir(const char *pathname);

The explain_chdir function is used to obtain an explanation of an error returned by the chdir(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. she's overachieving, we love that for her. ✨

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 (chdir(pathname) < 0)
{
    fprintf(stderr, '%s0, explain_chdir(pathname));
    exit(EXIT_FAILURE);
}

pathname — the original pathname, exactly as passed to the chdir(2) system call. don't be out here editing it, she wants it verbatim 🫶

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. so like… be careful, bestie 😭

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🦋 explain_errno_chdir

const char *explain_errno_chdir(int errnum, const char *pathname);

The explain_errno_chdir function is used to obtain an explanation of an error returned by the chdir(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. she read the whole error and then some. 💙

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

if (chdir(pathname) < 0)
{
    int err = errno;
    fprintf(stderr, '%s0, explain_errno_chdir(err, pathname));
    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. sneaky little functions, always touching your errno 🙈

pathname — the original pathname, exactly as passed to the chdir(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. fr fr, watch out. 💀

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🍓 explain_message_chdir

void explain_message_chdir(char *message, int message_size, const char *pathname);

The explain_message_chdir function is used to obtain an explanation of an error returned by the chdir(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:

if (chdir(pathname) < 0)
{
    char message[3000];
    explain_message_chdir(message, sizeof(message), pathname);
    fprintf(stderr, '%s0, message);
    exit(EXIT_FAILURE);
}

message — the location in which to store the returned message. Because a message return buffer has been supplied, this function is thread safe. glow up!! she brought her own buffer!! 👑

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 chdir(2) system call.

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🌈 explain_message_errno_chdir

void explain_message_errno_chdir(char *message, int message_size, int errnum, const char * pathname);

The explain_message_errno_chdir function is used to obtain an explanation of an error returned by the chdir(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. the final boss of error explanations. 💖

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

if (chdir(pathname) < 0)
{
    int err = errno;
    char message[3000];
    explain_message_errno_chdir(message, sizeof(message), err,
        pathname);
    fprintf(stderr, '%s0, message);
    exit(EXIT_FAILURE);
}

message — the location in which to store the returned message. Because a message return buffer has been supplied, this function is thread safe. she said "I'll bring my own storage" and honestly? queen. 💅

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. grab it early, bestie, or it's gone. 😭

pathname — the original pathname, exactly as passed to the chdir(2) system call.

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👑 COPYRIGHT 👑

libexplain version 1.4 Copyright (C) 2008 Peter Miller

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🧚 AUTHOR 🧚

Written by Peter Miller <pmiller@opensource.org.au> 🌸

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and that's the whole page, bestie 💜 that was explain_chdir(3) from libexplain version 1.4, © 2008 Peter Miller — go forth and explain your errors, you main character 🦋✨