explain_vfork(3)

✨ explain_vfork — bestie's guide to vfork(2) errors ✨

okay so this is explain_vfork(3), from the Library Functions Manual 💖 and it's literally the page that tells you how to get actual human explanations for when vfork(2) throws hands and returns an error. no cap.

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🌸 NAME 🌸

explain_vfork — explain vfork(2) errors. that's it. that's the whole vibe. it takes your mystery error and turns it into words you can read at 3am 🫶

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🎀 SYNOPSIS 🎀

#include <libexplain/vfork.h>
const char *explain_vfork(void);
const char *explain_errno_vfork(int errnum, void);
void explain_message_vfork(char *message, int message_size, void);
void explain_message_errno_vfork(char *message, int message_size, int
errnum, void);

four functions, four different flavours of "bestie, here's what went wrong" 💅

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🦋 DESCRIPTION 🦋

so like, these functions are the ones you call when vfork(2) returns an error and you're sitting there like what does this even mean. they give you explanations. iconic behaviour honestly.

⭐ explain_vfork ⭐

const char *explain_vfork(void);

explain_vfork gets you an explanation of an error that came back from the vfork(2) system call. the bare minimum it'll give you is the value of strerror(errno), but usually it does so much better than that and tells you the actual underlying cause in way more detail. it's giving overachiever and we love her 💖

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

Returns: the message explaining the error. and here's the tea — this message buffer is shared by all the libexplain functions that don't supply a buffer in their argument list. so the next call to any libexplain function that shares this buffer will just overwrite it. 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 too. periodt.

Example: this function is meant to be used in a fashion similar to this:

pid_t result = vfork();
if (result < 0)
{
    fprintf(stderr, "%s\n", explain_vfork());
    exit(EXIT_FAILURE);
}

and the above code example is available pre‐packaged as the explain_vfork_or_die(3) function. so if you're lazy (same) you can just use that 🍓

💜 explain_errno_vfork 💜

const char *explain_errno_vfork(int errnum, void);

explain_errno_vfork gets you an explanation of an error returned by the vfork(2) system call. least it'll contain is the value of strerror(errno), but usually it goes way harder and shows you the underlying cause in more detail ✨

• errnum — the error value to be decoded, usually grabbed from the errno global variable right before you call this function. and you need to do it that way if you have to run any code between the system call you're explaining and this function, because sooo many libc functions will mess with the value of errno. rude of them tbh.

Returns: the message explaining the error. same deal as before — this message buffer is shared by all libexplain functions that don't supply a buffer in their argument list, and it gets overwritten by the next call to any libexplain function sharing that buffer, other threads included. 💀

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

Example: meant to be used in a fashion similar to this:

pid_t result = vfork();
if (result < 0)
{
    int err = errno;
    fprintf(stderr, "%s\n", explain_errno_vfork(err, ));
    exit(EXIT_FAILURE);
}

and yup, the above code example is available pre‐packaged as the explain_vfork_or_die(3) function 🌈

🧚 explain_message_vfork 🧚

void explain_message_vfork(char *message, int message_size, void);

explain_message_vfork gets you an explanation of an error returned by the vfork(2) system call. minimum content is the value of strerror(errno), but usually it does much better and points at the underlying cause in more detail 👑

the errno global variable is what it uses to get the error value to be decoded.

• message — where to store the returned message. if you supply a suitable message return buffer, this function is thread safe. slay.
• message_size — the size in bytes of the location where you're storing the returned message.

Example: meant to be used in a fashion similar to this:

pid_t result = vfork();
if (result < 0)
{
    char message[3000];
    explain_message_vfork(message, sizeof(message), );
    fprintf(stderr, "%s\n", message);
    exit(EXIT_FAILURE);
}

and the above code example is available pre‐packaged as the explain_vfork_or_die(3) function 🎀

🌸 explain_message_errno_vfork 🌸

void explain_message_errno_vfork(char *message, int message_size, int
errnum, void);

explain_message_errno_vfork gets you an explanation of an error returned by the vfork(2) system call. the least the message will contain is the value of strerror(errno), but usually it does much better and shows you the underlying cause in more detail. main character energy fr fr.

• message — where 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 where you're storing the returned message.
• errnum — the error value to be decoded, usually taken from the errno global variable right before this function is called. 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.

Example: meant to be used in a fashion similar to this:

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

and the above code example is available pre‐packaged as the explain_vfork_or_die(3) function 🫶

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👑 SEE ALSO 👑

• vfork(2) — create a child process and block parent
• explain_vfork_or_die(3) — create a child process and block parent and report errors

iykyk, go read those next bestie 📚

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💖 COPYRIGHT 💖

libexplain version 1.4 Copyright (C) 2009 Peter Miller

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so yeah, that's the whole page 💅 it's from libexplain version 1.4, copyright (C) 2009 Peter Miller, and that's your cue to go forth and explain your vfork(2) errors like the icon you are. mwah 🎀✨