explain_tmpfile(3)

💖 explain_tmpfile — okay bestie, let's talk about tmpfile(3) errors 💖

this is a page from the Library Functions Manual, and it's all about explain_tmpfile — the libexplain glow-up that tells you why your tmpfile(3) call flopped instead of just leaving you on read 🫶

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✨ NAME ✨

explain_tmpfile — explain tmpfile(3) errors, i.e. the translator between "it broke 😭" and "here's literally why, bestie"

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🌸 SYNOPSIS 🌸

#include <libexplain/tmpfile.h>
const char *explain_tmpfile(void);
const char *explain_errno_tmpfile(int errnum, void);
void explain_message_tmpfile(char *message, int message_size, void);
void explain_message_errno_tmpfile(char *message, int message_size, int errnum, void);

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👑 DESCRIPTION 👑

okay so. these functions exist so you can get actual explanations for errors handed back by the tmpfile(3) system call. no cap, they're the group chat member who actually reads the error message 💅

🦋 explain_tmpfile 🦋

const char *explain_tmpfile(void);

explain_tmpfile gets you an explanation of an error returned by the tmpfile(3) system call. the bare minimum you'll get is the value of strerror(errno), but usually it does so much better and tells you the underlying cause in way more detail. it's giving detective energy 🔍

the errno global variable is what gets used to grab the error value that's gonna be decoded.

Returns: the message explaining the error. ⚠️ this message buffer is shared by all libexplain functions that don't take a buffer in their argument list. it will get overwritten by the next call to any libexplain function sharing that buffer — other threads included. so yeah, it's a communal water bottle situation 🙈

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.

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

FILE *result = tmpfile();
if (!result)
{
    fprintf(stderr, "%s\n", explain_tmpfile());
    exit(EXIT_FAILURE);
}

the above code example is available pre‐packaged as the explain_tmpfile_or_die(3) function. iconic of them tbh ✨

🌈 explain_errno_tmpfile 🌈

const char *explain_errno_tmpfile(int errnum, void);

explain_errno_tmpfile gets you an explanation of an error returned by the tmpfile(3) system call. the least the message will contain is the value of strerror(errno), but usually it goes way harder and points at 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 if you need to run any code between the system call being explained and this function, because a whole lot of libc functions will mess with the value of errno. protect your errno, bestie, it's fragile 🥺

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. it will be overwritten by the next call to any libexplain function that shares this buffer, including from 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 too.

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

FILE *result = tmpfile();
if (!result)
{
    int err = errno;
    fprintf(stderr, "%s\n", explain_errno_tmpfile(err, ));
    exit(EXIT_FAILURE);
}

the above code example is available pre‐packaged as the explain_tmpfile_or_die(3) function.

🎀 explain_message_tmpfile 🎀

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

explain_message_tmpfile gets you an explanation of an error returned by the tmpfile(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. obsessed 😌

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

• message — the location in which to store the returned message. if you supply a suitable message return buffer, this function is thread safe. look at you, being responsible 🫶
• 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:

FILE *result = tmpfile();
if (!result)
{
    char message[3000];
    explain_message_tmpfile(message, sizeof(message), );
    fprintf(stderr, "%s\n", message);
    exit(EXIT_FAILURE);
}

the above code example is available pre‐packaged as the explain_tmpfile_or_die(3) function.

⭐ explain_message_errno_tmpfile ⭐

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

explain_message_errno_tmpfile gets you an explanation of an error returned by the tmpfile(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. main character of error reporting fr fr 👑

• 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.

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

FILE *result = tmpfile();
if (!result)
{
    int err = errno;
    char message[3000];
    explain_message_errno_tmpfile(message, sizeof(message), err, );
    fprintf(stderr, "%s\n", message);
    exit(EXIT_FAILURE);
}

the above code example is available pre‐packaged as the explain_tmpfile_or_die(3) function.

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🧚 SEE ALSO 🧚

• tmpfile(3) — create a temporary file
• explain_tmpfile_or_die(3) — create a temporary file 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 💖 that was explain_tmpfile(3) from the Library Functions Manual — brought to you by libexplain version 1.4, with copyright vibes from Peter Miller back in 2009. slay, go forth and read your error messages 💅✨🦋