explain_setgroups(3)

✨ NAME ✨

explain_setgroups — bestie, this is the libexplain glow-up that explains setgroups(2) errors so you're never staring at a cryptic failure like 😭

It lives in the Library Functions Manual, and yes, it's giving main character energy in libexplain. 💅

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🎀 SYNOPSIS 🎀

#include <libexplain/setgroups.h>
const char *explain_setgroups(size_t data_size, const gid_t *data);
const char *explain_errno_setgroups(int errnum, size_t data_size, const gid_t *data);
void explain_message_setgroups(char *message, int message_size, size_t data_size, const gid_t *data);
void explain_message_errno_setgroups(char *message, int message_size, int errnum, size_t data_size, const gid_t *data);

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🦋 DESCRIPTION 🦋

Okay so these functions? They're your little translators. 🌸 You use them to get explanations for errors returned by the setgroups(2) system call. No cap, they're literally just here to tell you what went wrong and why.

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💖 explain_setgroups 💖

const char *explain_setgroups(size_t data_size, const gid_t *data);

The explain_setgroups function is used to obtain an explanation of an error returned by the setgroups(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. Slay. ✨

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

• data_size — The original data_size, exactly as passed to the setgroups(2) system call.
• data — The original data, exactly as passed to the setgroups(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. iykyk — don't get caught lacking in a multithreaded situation, bestie. 💀

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

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

The above code example is available pre‐packaged as the explain_setgroups_or_die(3) function. 🎁

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💅 explain_errno_setgroups 💅

const char *explain_errno_setgroups(int errnum, size_t data_size, const gid_t *data);

The explain_errno_setgroups function is used to obtain an explanation of an error returned by the setgroups(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. Obsessed, honestly. 🌈

• 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. 😤
• data_size — The original data_size, exactly as passed to the setgroups(2) system call.
• data — The original data, exactly as passed to the setgroups(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. 🚩

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

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

The above code example is available pre‐packaged as the explain_setgroups_or_die(3) function. 🎀

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🧚 explain_message_setgroups 🧚

void explain_message_setgroups(char *message, int message_size, size_t data_size, const gid_t *data);

The explain_message_setgroups function is used to obtain an explanation of an error returned by the setgroups(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. Periodt. ✨

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

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

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

The above code example is available pre‐packaged as the explain_setgroups_or_die(3) function. 👑

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🌟 explain_message_errno_setgroups 🌟

void explain_message_errno_setgroups(char *message, int message_size, int errnum, size_t data_size, const gid_t *data);

The explain_message_errno_setgroups function is used to obtain an explanation of an error returned by the setgroups(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 ate, no crumbs. 🔥

• 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. 🙈
• data_size — The original data_size, exactly as passed to the setgroups(2) system call.
• data — The original data, exactly as passed to the setgroups(2) system call.

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

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

The above code example is available pre‐packaged as the explain_setgroups_or_die(3) function. 🍓

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🌈 SEE ALSO 🌈

• setgroups(2) — get/set list of supplementary group IDs
• explain_setgroups_or_die(3) — get/set list of supplementary group IDs and report errors

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👑 COPYRIGHT 👑

• libexplain version 1.4
• Copyright (C) 2009 Peter Miller

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okay that's the whole page bestie, you're officially a setgroups(2) error-decoding icon 💅✨ this was explain_setgroups(3) from the Library Functions Manual, libexplain version 1.4, Copyright (C) 2009 Peter Miller, and it says explain_setgroups(3) at the bottom because of course it does 🎀 bye ily 🫶