explain_getgrouplist(3)

💅 explain_getgrouplist — the whole manual, bestie edition ✨

okay so this is the manual page for explain_getgrouplist from the Library Functions Manual — it lives in section 3 of your man pages, iykyk. grab a snack, we're decoding getgrouplist(3) errors together 🫶

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🌸 NAME 🌸

explain_getgrouplist — bestie, this is here to explain getgrouplist(3) errors for you 💖

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✨ SYNOPSIS ✨

#include <libexplain/getgrouplist.h>
const char *explain_getgrouplist(const char *user, gid_t group, gid_t
*groups, int *ngroups);
const char *explain_errno_getgrouplist(int errnum, const char *user,
gid_t group, gid_t *groups, int *ngroups);
void explain_message_getgrouplist(char *message, int message_size, const
char *user, gid_t group, gid_t *groups, int *ngroups);
void explain_message_errno_getgrouplist(char *message, int message_size,
int errnum, const char *user, gid_t group, gid_t *groups, int *ngroups);

like. four whole functions. one iconic mission. 💅

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🦋 DESCRIPTION 🦋

These functions are here so you can get actual explanations for errors returned by the getgrouplist(3) system call. no more staring at a bare errno like 🧍‍♀️ — these give you the tea ☕

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🌈 explain_getgrouplist

const char *explain_getgrouplist(const char *user, gid_t group, gid_t
*groups, int *ngroups);

The explain_getgrouplist function is used to obtain an explanation of an error returned by the getgrouplist(3) 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 ate, honestly 💅

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

• user — The original user, exactly as passed to the getgrouplist(3) system call.
• group — The original group, exactly as passed to the getgrouplist(3) system call.
• groups — The original groups, exactly as passed to the getgrouplist(3) system call.
• ngroups — The original ngroups, exactly as passed to the getgrouplist(3) 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:

errno = 0;
if (getgrouplist(user, group, groups, ngroups) < 0 && errno != 0)
{
    fprintf(stderr, "%s\n", explain_getgrouplist(user, group,
    groups, ngroups));
    exit(EXIT_FAILURE);
}

The above code example is available pre-packaged as the explain_getgrouplist_or_die(3) function. cute, right? 🎀

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💜 explain_errno_getgrouplist

const char *explain_errno_getgrouplist(int errnum, const char *user,
gid_t group, gid_t *groups, int *ngroups);

The explain_errno_getgrouplist function is used to obtain an explanation of an error returned by the getgrouplist(3) 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.

• 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. so like. grab it fast bestie 🏃‍♀️
• user — The original user, exactly as passed to the getgrouplist(3) system call.
• group — The original group, exactly as passed to the getgrouplist(3) system call.
• groups — The original groups, exactly as passed to the getgrouplist(3) system call.
• ngroups — The original ngroups, exactly as passed to the getgrouplist(3) 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:

errno = 0;
if (getgrouplist(user, group, groups, ngroups) < 0 && errno != 0)
{
    int err = errno;
    fprintf(stderr, "%s\n", explain_errno_getgrouplist(err, user,
    group, groups, ngroups));
    exit(EXIT_FAILURE);
}

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

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🎀 explain_message_getgrouplist

void explain_message_getgrouplist(char *message, int message_size, const
char *user, gid_t group, gid_t *groups, int *ngroups);

The explain_message_getgrouplist function is used to obtain an explanation of an error returned by the getgrouplist(3) 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.

• 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.
• user — The original user, exactly as passed to the getgrouplist(3) system call.
• group — The original group, exactly as passed to the getgrouplist(3) system call.
• groups — The original groups, exactly as passed to the getgrouplist(3) system call.
• ngroups — The original ngroups, exactly as passed to the getgrouplist(3) system call.

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

errno = 0;
if (getgrouplist(user, group, groups, ngroups) < 0 && errno != 0)
{
    char message[3000];
    explain_message_getgrouplist(message, sizeof(message), user,
    group, groups, ngroups);
    fprintf(stderr, "%s\n", message);
    exit(EXIT_FAILURE);
}

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

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🍓 explain_message_errno_getgrouplist

void explain_message_errno_getgrouplist(char *message, int message_size,
int errnum, const char *user, gid_t group, gid_t *groups, int *ngroups);

The explain_message_errno_getgrouplist function is used to obtain an explanation of an error returned by the getgrouplist(3) 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.

• 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.
• user — The original user, exactly as passed to the getgrouplist(3) system call.
• group — The original group, exactly as passed to the getgrouplist(3) system call.
• groups — The original groups, exactly as passed to the getgrouplist(3) system call.
• ngroups — The original ngroups, exactly as passed to the getgrouplist(3) system call.

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

errno = 0;
if (getgrouplist(user, group, groups, ngroups) < 0 && errno != 0)
{
    int err = errno;
    char message[3000];
    explain_message_errno_getgrouplist(message, sizeof(message),
    err, user, group, groups, ngroups);
    fprintf(stderr, "%s\n", message);
    exit(EXIT_FAILURE);
}

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

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👀 SEE ALSO 👀

• getgrouplist(3) — get list of groups to which a user belongs
• explain_getgrouplist_or_die(3) — get list of groups to which a user belongs and report errors

like yes go read those too, they're the moment 💅

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💖 COPYRIGHT 💖

okay final vibe check, bestie — this page is from libexplain version 1.4, and the copyright belongs to Copyright (C) 2013 Peter Miller. iconic. legendary. protected by law and also by my love 🫶✨ thank u for reading, mwah 💋

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