explain_truncate(3)

✨ explain_truncate — a whole vibe ✨

okay bestie, welcome to explain_truncate(3) from the Library Functions Manual 💜 no cap, this one is a libexplain page and it is so useful, iykyk.

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🌸 NAME 🌸

explain_truncate — bestie, this is the one that explains truncate(2) errors 💅

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🎀 SYNOPSIS 🎀

#include <libexplain/truncate.h>
const char *explain_truncate(const char *pathname, long long length);
const char *explain_errno_truncate(int errnum, const char *pathname,
long long length);
void explain_message_truncate(char *message, int message_size, const
char *pathname, long long length);
void explain_message_errno_truncate(char *message, int message_size, int
errnum, const char *pathname, long long length);

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🦋 DESCRIPTION 🦋

so like, these functions? they're your little translators 💖 you use them to get actual explanations for errors that the truncate(2) system call hands back to you. not just "something broke" — real detail. slay.

💫 explain_truncate

const char *explain_truncate(const char *pathname, long long length);

explain_truncate is the girl you call when truncate(2) returns an error and you want the tea ☕ the absolute least you'll get back is the value of strerror(errno), but usually it does so much better than that and tells you the actual underlying cause in more detail. main character energy fr fr.

the errno global variable is what it reads to figure out which error value to decode 👑

this function is meant to be used in a fashion similar to the following example:

if (truncate(pathname, length) < 0)
{
    fprintf(stderr, "%s\n", explain_truncate(pathname, length));
    exit(EXIT_FAILURE);
}

• pathname — the original pathname, exactly as passed to the truncate(2) system call. no edits, no remixes, exactly.
• length — the original length, exactly as passed to the truncate(2) system call. same deal.

Returns: the message explaining the error 💌 but bestie, listen — this message buffer is shared by all libexplain functions that don't supply a buffer in their argument list. it will get overwritten by the very next call to any libexplain function that shares this buffer, including calls from other threads. so don't get attached 😭

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. it's giving "one shared notebook for the whole group chat" 💀

💫 explain_errno_truncate

const char *explain_errno_truncate(int errnum, const char *pathname,
long long length);

explain_errno_truncate does the same thing — it gets you an explanation of an error returned by the truncate(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. obsessed.

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

if (truncate(pathname, length) < 0)
{
    int err = errno;
    fprintf(stderr, "%s\n", explain_errno_truncate(err, pathname, length));
    exit(EXIT_FAILURE);
}

• errnum — the error value to be decoded, usually grabbed from the errno global variable right before this function is called. this matters if you need to run any code between the system call you're explaining and this function, because a whole bunch of libc functions will change the value of errno on you 🙈
• pathname — the original pathname, exactly as passed to the truncate(2) system call.
• length — the original length, exactly as passed to the truncate(2) system call.

Returns: the message explaining the error ✨ again — 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.

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_message_truncate

void explain_message_truncate(char *message, int message_size, const
char *pathname, long long length);

explain_message_truncate may be used to obtain an explanation of an error returned by the truncate(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 (truncate(pathname, length) < 0)
{
    char message[3000];
    explain_message_truncate(message, sizeof(message), pathname, length);
    fprintf(stderr, "%s\n", message);
    exit(EXIT_FAILURE);
}

• message — the location in which to store the returned message. and here's the cute part: if you supply a suitable message return buffer, this function is thread safe 🫶 you did that.
• 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 truncate(2) system call.
• length — the original length, exactly as passed to the truncate(2) system call.

💫 explain_message_errno_truncate

void explain_message_errno_truncate(char *message, int message_size, int
errnum, const char *pathname, long long length);

explain_message_errno_truncate may be used to obtain an explanation of an error returned by the truncate(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. iconic.

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

if (truncate(pathname, length) < 0)
{
    int err = errno;
    char message[3000];
    explain_message_errno_truncate(message, sizeof(message), err,
        pathname, length);
    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. do not skip this step bestie 😭
• pathname — the original pathname, exactly as passed to the truncate(2) system call.
• length — the original length, exactly as passed to the truncate(2) system call.

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🌟 SEE ALSO 🌟

• truncate(2) — truncate a file to a specified length
• explain_truncate_or_die(3) — truncate a file to a specified length 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, you ate it up fr fr 🍓✨ sending you off with love from explain_truncate(3), libexplain version 1.4, copyright 2008 Peter Miller — mwah, go forth and debug 💅💖🦋