explain_timerfd_create(3)

👑 NAME 👑

explain_timerfd_create — okay so this is the glow-up for timerfd_create(2) errors: it takes whatever went wrong and explains it to you like a bestie who actually read the docs. This is a page from the Library Functions Manual (section 3, the library girlies 🫶).

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✨ SYNOPSIS ✨

#include <libexplain/timerfd_create.h>
const char *explain_timerfd_create(int clockid, int flags);
const char *explain_errno_timerfd_create(int errnum, int clockid, int flags);
void explain_message_timerfd_create(char *message, int message_size, int clockid, int flags);
void explain_message_errno_timerfd_create(char *message, int message_size, int errnum, int clockid, int flags);

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💅 DESCRIPTION 💅

So like, these functions are your little translators 💖 — you use them to get explanations for errors that the timerfd_create(2) system call throws back at you. No more squinting at a bare errno like "girl what does that MEAN".

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🌸 explain_timerfd_create 🌸

const char *explain_timerfd_create(int clockid, int flags);

The explain_timerfd_create function hands you an explanation of an error that came back from the timerfd_create(2) system call. The least the message will contain is the value of strerror(errno) — but usually it goes so much harder and tells you the actual underlying cause in more detail. It's giving detective energy 🔍.

The errno global variable is what it uses to grab the error value that needs decoding.

• clockid — the original clockid, exactly as passed to the timerfd_create(2) system call. No edits, no notes, verbatim periodt.
• flags — the original flags, exactly as passed to the timerfd_create(2) system call. Also verbatim, we don't gatekeep.

Returns:

The message explaining the error. ⚠️ Heads up bestie: 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 calls from other threads. So don't be clinging to it.

Note: This function is not thread safe, because it shares a return buffer across all threads, and many other functions in this library do the same. Lowkey a situationship with that buffer 😭.

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

int result = timerfd_create(clockid, flags);
if (result < 0)
{
    fprintf(stderr, "%s\n", explain_timerfd_create(clockid, flags));
    exit(EXIT_FAILURE);
}

The above code example is available pre-packaged as the explain_timerfd_create_or_die(3) function. Slay, someone already did the work for you ✨.

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🦋 explain_errno_timerfd_create 🦋

const char *explain_errno_timerfd_create(int errnum, int clockid, int flags);

The explain_errno_timerfd_create function is also here to obtain an explanation of an error returned by the timerfd_create(2) system call. Same deal: 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. Iconic behaviour honestly 👑.

• errnum — the error value to be decoded, usually grabbed from the errno global variable just before this function is called. Why though? Because if you need to call any code between the system call you're explaining and this function, a lot of libc functions will alter the value of errno and ruin everything 💀. So snapshot it early.
• clockid — the original clockid, exactly as passed to the timerfd_create(2) system call.
• flags — the original flags, exactly as passed to the timerfd_create(2) system call.

Returns:

The message explaining the error. That message buffer is shared by all libexplain functions which do not supply a buffer in their argument list, and it will be overwritten by the next call to any libexplain function which shares this buffer — including other threads. Keep up bestie.

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.

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

int result = timerfd_create(clockid, flags);
if (result < 0)
{
    int err = errno;
    fprintf(stderr, "%s\n", explain_errno_timerfd_create(err, clockid, flags));
    exit(EXIT_FAILURE);
}

The above code example is available pre-packaged as the explain_timerfd_create_or_die(3) function. Free real estate 🎀.

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🎀 explain_message_timerfd_create 🎀

void explain_message_timerfd_create(char *message, int message_size, int clockid, int flags);

The explain_message_timerfd_create function is used to obtain an explanation of an error returned by the timerfd_create(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 thorough 💅.

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

• message — the location in which to store the returned message. ✨ Big news: if you supply a suitable message return buffer, this function is thread safe. Your own buffer, your own peace.
• message_size — the size in bytes of the location in which to store the returned message.
• clockid — the original clockid, exactly as passed to the timerfd_create(2) system call.
• flags — the original flags, exactly as passed to the timerfd_create(2) system call.

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

int result = timerfd_create(clockid, flags);
if (result < 0)
{
    char message[3000];
    explain_message_timerfd_create(message, sizeof(message), clockid, flags);
    fprintf(stderr, "%s\n", message);
    exit(EXIT_FAILURE);
}

The above code example is available pre-packaged as the explain_timerfd_create_or_die(3) function.

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💜 explain_message_errno_timerfd_create 💜

void explain_message_errno_timerfd_create(char *message, int message_size, int errnum, int clockid, int flags);

The explain_message_errno_timerfd_create function is used to obtain an explanation of an error returned by the timerfd_create(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 full combo meal 🍓.

• message — the location in which to store the returned message. If a suitable message return buffer is supplied, this function is thread safe. Your buffer, your rules.
• 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. Save it before it ghosts you 🙈.
• clockid — the original clockid, exactly as passed to the timerfd_create(2) system call.
• flags — the original flags, exactly as passed to the timerfd_create(2) system call.

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

int result = timerfd_create(clockid, flags);
if (result < 0)
{
    int err = errno;
    char message[3000];
    explain_message_errno_timerfd_create(message, sizeof(message), err, clockid, flags);
    fprintf(stderr, "%s\n", message);
    exit(EXIT_FAILURE);
}

The above code example is available pre-packaged as the explain_timerfd_create_or_die(3) function.

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🌈 SEE ALSO 🌈

• timerfd_create(2) — timers that notify via file descriptors
• explain_timerfd_create_or_die(3) — timers that notify via file descriptors and report errors

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⭐ COPYRIGHT ⭐

libexplain version 1.4 Copyright (C) 2009 Peter Miller

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And that's the whole page bestie 💖 — go forth, explain those errors, and remember: it's libexplain version 1.4, Copyright (C) 2009 Peter Miller, explain_timerfd_create(3), and you ate. No cap. 👑✨