explain_fputs(3)

💖 explain_fputs — a whole manual page, bestie edition 💖

okay so. this is explain_fputs, straight out of the Library Functions Manual, and it's literally here to help you understand why fputs(3) threw hands at you. 🫶

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✨ NAME ✨

explain_fputs — bestie, it explains fputs(3) errors. that's it. that's the job. 💅

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🌸 SYNOPSIS 🌸

#include <libexplain/fputs.h>
const char *explain_fputs(const char *s, FILE *fp);
const char *explain_errno_fputs(int errnum, const char *s, FILE *fp);
void explain_message_fputs(char *message, int message_size, const char *s, FILE *fp);
void explain_message_errno_fputs(char *message, int message_size, int errnum, const char *s, FILE *fp);

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🦋 DESCRIPTION 🦋

these functions? they're your little translators. you hit an error coming back from the fputs(3) system call, and these girls turn that sad little number into an actual explanation. no cap. 💜

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🎀 explain_fputs 🎀

const char *explain_fputs(const char *s, FILE *fp);

the explain_fputs function gets you an explanation of an error returned by the fputs(3) system call. the absolute bare minimum it will give you is the value of strerror(errno) — but lowkey it usually does way better than that and tells you the actual underlying cause in more detail. iconic behaviour honestly. ✨

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

• s — the original s, exactly as passed to the fputs(3) system call. like, we are NOT paraphrasing her.
• fp — the original fp, exactly as passed to the fputs(3) system call. same energy.

Returns: the message explaining the error. this message buffer is shared by all the libexplain functions that don't supply a buffer in their argument list. so yeah — it gets 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 do the same. know that before you start anything spicy with threads. 🙈

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

if (fputs(s, fp) < 0)
{
    fprintf(stderr, "%s\n", explain_fputs(s, fp));
    exit(EXIT_FAILURE);
}

the above code example is available pre-packaged as the explain_fputs_or_die(3) function. slay, no notes. 👑

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🌈 explain_errno_fputs 🌈

const char *explain_errno_fputs(int errnum, const char *s, FILE *fp);

the explain_errno_fputs function gets you an explanation of an error returned by the fputs(3) system call. again, the least the message will contain is the value of strerror(errno), but usually it will do much better and point at the underlying cause in more detail. she's thorough. 🎀

• 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 bestie, a LOT of libc functions will alter the value of errno on you. 😭
• s — the original s, exactly as passed to the fputs(3) system call.
• fp — the original fp, exactly as passed to the fputs(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. it will be overwritten by the next call to any libexplain function which shares this buffer, including other threads. yes, again. 💀

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:

if (fputs(s, fp) < 0)
{
    int err = errno;
    fprintf(stderr, "%s\n", explain_errno_fputs(err, s, fp));
    exit(EXIT_FAILURE);
}

the above code example is available pre-packaged as the explain_fputs_or_die(3) function. periodt. 💅

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🧚 explain_message_fputs 🧚

void explain_message_fputs(char *message, int message_size, const char *s, FILE *fp);

the explain_message_fputs function is used to obtain an explanation of an error returned by the fputs(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. look at her go. ✨
• message_size — the size in bytes of the location in which to store the returned message.
• s — the original s, exactly as passed to the fputs(3) system call.
• fp — the original fp, exactly as passed to the fputs(3) system call.

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

if (fputs(s, fp) < 0)
{
    char message[3000];
    explain_message_fputs(message, sizeof(message), s, fp);
    fprintf(stderr, "%s\n", message);
    exit(EXIT_FAILURE);
}

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

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⭐ explain_message_errno_fputs ⭐

void explain_message_errno_fputs(char *message, int message_size, int errnum, const char *s, FILE *fp);

the explain_message_errno_fputs function is used to obtain an explanation of an error returned by the fputs(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 and left no crumbs. 🔥

• 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. 🙈
• s — the original s, exactly as passed to the fputs(3) system call.
• fp — the original fp, exactly as passed to the fputs(3) system call.

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

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

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

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👑 SEE ALSO 👑

• fputs(3) — write a string to a stream
• explain_fputs_or_die(3) — write a string to a stream 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!! libexplain version 1.4, copyright (C) 2009 Peter Miller — mwah, go forth and debug, you've got this 💅🎀✨