explain_sethostname(3)

💖 explain_sethostname — the tea on your sethostname(2) errors 💖

okay bestie, this is a page from the Library Functions Manual, and it's all about explain_sethostname, a lil function fam that tells you why sethostname(2) said no. no cap, it's giving "translator for syscall drama." 🎀

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✨ NAME ✨

explain_sethostname — explain sethostname(2) errors 💅

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🌸 SYNOPSIS 🌸

#include <libexplain/sethostname.h>
const char *explain_sethostname(const char *name, size_t name_size);
const char *explain_errno_sethostname(int errnum, const char *name,
size_t name_size);
void explain_message_sethostname(char *message, int message_size, const
char *name, size_t name_size);
void explain_message_errno_sethostname(char *message, int message_size,
int errnum, const char *name, size_t name_size);

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🦋 DESCRIPTION 🦋

So like, these functions are the ones you call to get actual explanations for errors that come back from the sethostname(2) system call. think of them as the friend who reads the cryptic error and goes "okay so here's what actually happened." 🫶

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💜 explain_sethostname

const char *explain_sethostname(const char *name, size_t name_size);

The explain_sethostname function is your go-to for getting an explanation of an error that sethostname(2) returned. The least the message will contain is the value of strerror(errno), but usually it does way better and points at the actual underlying cause in more detail. ate. 👑

The errno global variable is what it uses to grab the error value it's gonna decode.

This one is meant to be used in a vibe similar to this example:

if (sethostname(name, name_size) < 0)
{
    fprintf(stderr, "%s\n", explain_sethostname(name, name_size));
    exit(EXIT_FAILURE);
}

That code example up there? It's available pre-packaged as the explain_sethostname_or_die(3) function. convenient fr fr ✨

• name — The original name, exactly as passed to the sethostname(2) system call.
• name_size — The original name_size, exactly as passed to the sethostname(2) system call.

Returns: The message explaining the error. This message buffer is shared by all libexplain functions that don't supply a buffer in their argument list. So it gets overwritten by the next call to any libexplain function that shares this buffer — including calls from other threads. 😭

Note: This function is not thread safe, because it shares a return buffer across all threads, and honestly, so do many other functions in this library. not me finding out the hard way 💀

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🌈 explain_errno_sethostname

const char *explain_errno_sethostname(int errnum, const char *name,
size_t name_size);

The explain_errno_sethostname function is used to obtain an explanation of an error returned by the sethostname(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. 💖

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

if (sethostname(name, name_size) < 0)
{
    int err = errno;
    fprintf(stderr, "%s\n", explain_errno_sethostname(err, name, name_size));
    exit(EXIT_FAILURE);
}

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

• 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 being explained and this function, because many libc functions will alter the value of errno. like, they're messy, lowkey 🙈
• name — The original name, exactly as passed to the sethostname(2) system call.
• name_size — The original name_size, exactly as passed to the sethostname(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. same energy as above, bestie 💀

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🍓 explain_message_sethostname

void explain_message_sethostname(char *message, int message_size, const
char *name, size_t name_size);

The explain_message_sethostname function is used to obtain an explanation of an error returned by the sethostname(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 errno global variable will be used to obtain the error value to be decoded.

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

if (sethostname(name, name_size) < 0)
{
    char message[3000];
    explain_message_sethostname(message, sizeof(message), name, name_size);
    fprintf(stderr, "%s\n", message);
    exit(EXIT_FAILURE);
}

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

• message — The location in which to store the returned message. If a suitable message return buffer is supplied, this function is thread safe. okay periodt, we love a safe one 👑
• message_size — The size in bytes of the location in which to store the returned message.
• name — The original name, exactly as passed to the sethostname(2) system call.
• name_size — The original name_size, exactly as passed to the sethostname(2) system call.

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🧚 explain_message_errno_sethostname

void explain_message_errno_sethostname(char *message, int message_size,
int errnum, const char *name, size_t name_size);

The explain_message_errno_sethostname function is used to obtain an explanation of an error returned by the sethostname(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. 🌸

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

if (sethostname(name, name_size) < 0)
{
    int err = errno;
    char message[3000];
    explain_message_errno_sethostname(message, sizeof(message), err, name,
        name_size);
    fprintf(stderr, "%s\n", message);
    exit(EXIT_FAILURE);
}

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

• 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. (they're always in your business, ngl)
• name — The original name, exactly as passed to the sethostname(2) system call.
• name_size — The original name_size, exactly as passed to the sethostname(2) system call.

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👀 SEE ALSO 👀

• sethostname(2) — get/set hostname
• explain_sethostname_or_die(3) — get/set hostname 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, no notes. 🌟 this was explain_sethostname(3) from the Library Functions Manual, brought to you by libexplain version 1.4 and Copyright (C) 2009 Peter Miller — go forth and explain your errors, icon. 💖✨🎀