explain_gethostid(3)

✨ explain_gethostid — the manual page, but make it make sense ✨

okay bestie, welcome to explain_gethostid(3) 💖 this one lives in the Library Functions Manual section of your man pages, and it's literally here to translate gethostid(3) errors from cryptic nonsense into actual human words. no cap. let's get into it 🫶

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🌸 NAME 🌸

explain_gethostid — bestie, this is the one that explains gethostid(3) errors to you 💅

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🎀 SYNOPSIS 🎀

#include <libexplain/gethostid.h>
const char *explain_gethostid(void);
const char *explain_errno_gethostid(int errnum, void);
void explain_message_gethostid(char *message, int message_size, void);
void explain_message_errno_gethostid(char *message, int message_size,
int errnum, void);

like, that's the whole lineup 👑 four little functions, all here to hold your hand.

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🦋 DESCRIPTION 🦋

so the vibe is: these functions exist so you can get explanations for errors that the gethostid(3) system call hands back to you. that's it, that's the whole job 🍓

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💜 explain_gethostid

const char *explain_gethostid(void);

explain_gethostid is the function you call when you wanna know why gethostid(3) returned an error. the absolute bare minimum you'll get back is the value of strerror(errno), but honestly? usually it does so much better and points at the actual underlying cause with way more detail. it's giving overachiever ✨

the errno global variable is what 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 the libexplain functions that don't take a buffer in their argument list. so it gets overwritten the next time any libexplain function that shares this buffer is called, 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. be careful out there bestie 💀

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

errno = 0;
long result = gethostid();
if (result < 0 || errno != 0)
{
    fprintf(stderr, "%s\n", explain_gethostid());
    exit(EXIT_FAILURE);
}

and the above code example is available pre-packaged as the explain_gethostid_or_die(3) function. iconic, honestly 🌈

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💖 explain_errno_gethostid

const char *explain_errno_gethostid(int errnum, void);

explain_errno_gethostid does the same thing — it gets you an explanation of an error returned by the gethostid(3) system call. again, the least the message will 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. you need this if you're gonna run any code between the system call you're explaining and this function, because so many libc functions will change the value of errno on you 🙈

Returns: the message explaining the error. and again, that message buffer is shared by all libexplain functions that don't supply a buffer in their argument list. it'll be overwritten by the next call to any libexplain function sharing this buffer, including other threads.

Note: not thread safe either, same reason — shared return buffer across all threads, plus many other functions in this library. periodt.

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

errno = 0;
long result = gethostid();
if (result < 0 || errno != 0)
{
    int err = errno;
    fprintf(stderr, "%s\n", explain_errno_gethostid(err, ));
    exit(EXIT_FAILURE);
}

and yes, this example is available pre-packaged as explain_gethostid_or_die(3) 💅

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🎀 explain_message_gethostid

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

explain_message_gethostid — same mission, obtain an explanation of an error returned by the gethostid(3) system call. least you'll get is strerror(errno), but usually it does much better and tells you the underlying cause in more detail 🦋

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

message — the location in which to store the returned message. and here's the slay: if you supply a suitable message return buffer, this function is thread safe 👑

message_size — the size in bytes of the location in which to store the returned message.

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

errno = 0;
long result = gethostid();
if (result < 0 || errno != 0)
{
    char message[3000];
    explain_message_gethostid(message, sizeof(message), );
    fprintf(stderr, "%s\n", message);
    exit(EXIT_FAILURE);
}

pre-packaged as explain_gethostid_or_die(3), as always 💖

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🌟 explain_message_errno_gethostid

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

explain_message_errno_gethostid is here to obtain an explanation of an error returned by the gethostid(3) system call. bare minimum is the value of strerror(errno), but usually it'll do much better and point out the underlying cause in more detail ✨

message — the location in which to store the returned message. supply a suitable message return buffer and 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 taken from the errno global variable just before this function is called. you need it if you have to run any code between the system call being explained and this function, because lots of libc functions will alter errno 😭

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

errno = 0;
long result = gethostid();
if (result < 0 || errno != 0)
{
    int err = errno;
    char message[3000];
    explain_message_errno_gethostid(message, sizeof(message),
    err, );
    fprintf(stderr, "%s\n", message);
    exit(EXIT_FAILURE);
}

and obviously, this example is available pre-packaged as the explain_gethostid_or_die(3) function 🌈

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👀 SEE ALSO 👀

• gethostid(3) — get the unique identifier of the current host
• explain_gethostid_or_die(3) — get the unique identifier of the current host and report errors

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📜 COPYRIGHT 📜

• libexplain version 1.4
• Copyright (C) 2013 Peter Miller

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and that's the whole page bestie, you ate that 💅 mwah 🎀

signed off from the explain_gethostid(3) corner of the Library Functions Manual, brought to you by libexplain version 1.4 and Copyright (C) 2013 Peter Miller — stay slaying, and may your errno always be zero 💖✨