explain_setgrent(3)

💅 NAME 💅

okay so bestie, this is explain_setgrent(3) from the Library Functions Manual, and it's literally the whole glow-up for setgrent(3) errors — it explains them. that's the vibe. ✨

🎀 SYNOPSIS 🎀

#include <libexplain/setgrent.h>
const char *explain_setgrent(void);
const char *explain_errno_setgrent(int errnum, void);
void explain_message_setgrent(char *message, int message_size, void);
void explain_message_errno_setgrent(char *message, int message_size, int
errnum, void);

🌸 DESCRIPTION 🌸

these functions are your little besties for getting explanations when the setgrent(3) system call comes back with an error. no cap. 🫶

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💖 explain_setgrent

const char *explain_setgrent(void);

the explain_setgrent function is what you call to snag an explanation of an error that setgrent(3) threw back at you. the bare minimum the message will have is the value of strerror(errno), but honestly? usually it does way better and tells you the actual underlying cause in way more detail. it's giving detective energy. 🔍

the errno global variable is the one that gets used to grab the error value that needs decoding.

Returns:

the message explaining the error. heads up though — this message buffer is shared by all libexplain functions that don't hand you their own buffer in the argument list. so it gets overwritten by the next call to any libexplain function sharing that buffer, including from other threads. 😭

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. periodt.

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

errno = 0;
void result = setgrent();
if (result < 0 && errno != 0)
{
    fprintf(stderr, "%s\n", explain_setgrent());
    exit(EXIT_FAILURE);
}

the above code example is available pre-packaged as the explain_setgrent_or_die(3) function. iconic. ✨

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🦋 explain_errno_setgrent

const char *explain_errno_setgrent(int errnum, void);

the explain_errno_setgrent function is used to obtain an explanation of an error returned by the setgrent(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 grabbed from the errno global variable right before this function is called. this matters because if you need to run any code between the system call being explained and this function, you have to save it first — so many libc functions will mess with the value of errno. 💀

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;
void result = setgrent();
if (result < 0 && errno != 0)
{
    int err = errno;
    fprintf(stderr, "%s\n", explain_errno_setgrent(err, ));
    exit(EXIT_FAILURE);
}

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

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🧚 explain_message_setgrent

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

the explain_message_setgrent function is used to obtain an explanation of an error returned by the setgrent(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.

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

errno = 0;
void result = setgrent();
if (result < 0 && errno != 0)
{
    char message[3000];
    explain_message_setgrent(message, sizeof(message), );
    fprintf(stderr, "%s\n", message);
    exit(EXIT_FAILURE);
}

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

---

🌈 explain_message_errno_setgrent

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

the explain_message_errno_setgrent function is used to obtain an explanation of an error returned by the setgrent(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. lowkey important fr fr.

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

errno = 0;
void result = setgrent();
if (result < 0 && errno != 0)
{
    int err = errno;
    char message[3000];
    explain_message_errno_setgrent(message, sizeof(message), err,
    );
    fprintf(stderr, "%s\n", message);
    exit(EXIT_FAILURE);
}

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

🔥 SEE ALSO 🔥

• setgrent(3) — rewind to the start of the group database
• explain_setgrent_or_die(3) — rewind to the start of the group database and report errors

👑 COPYRIGHT 👑

libexplain version 1.4 Copyright (C) 2013 Peter Miller

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okay bestie that's the whole page, you ate it up 💅✨ and just so you know who to thank, this was libexplain version 1.4, copyright © 2013 Peter Miller — go be the main character of your own error handling, mwah 🎀💖🦋