explain_getc(3)

💖 explain_getc — bestie edition 💖

okay so real talk, this is explain_getc(3) from the Library Functions Manual, and it's literally the glow-up your error messages have been begging for. it's the manual page for explain_getc, which explains getc(3) errors. no cap. ✨

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🌸 NAME 🌸

explain_getc — explain getc(3) errors

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🎀 SYNOPSIS 🎀

#include <libexplain/getc.h>
const char *explain_getc(FILE *fp);
const char *explain_errno_getc(int errnum, FILE *fp);
void explain_message_getc(char *message, int message_size, FILE *fp);
void explain_message_errno_getc(char *message, int message_size, int
errnum, FILE *fp);

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✨ DESCRIPTION ✨

so these functions?? they're your little translators 💅 you use them to get explanations for errors that the getc(3) system call hands back to you. it's giving "tell me what actually went wrong, in words, please".

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🦋 explain_getc 🦋

const char *explain_getc(FILE *fp);

the explain_getc function is what you call to obtain an explanation of an error returned by the getc(3) system call. the least the message will contain is the value of strerror(errno), but usually it's gonna do so much better and point at the underlying cause in way more detail. iconic behavior fr fr.

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:

int c = getc(fp);
if (c == EOF && ferror(fp))
{
    fprintf(stderr, "%s\n", explain_getc(fp));
    exit(EXIT_FAILURE);
}

• fp — the original fp, exactly as passed to the getc(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. 😭

Note: this function is not thread safe, because it shares a return buffer across all threads, and many other functions in this library.

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🌈 explain_errno_getc 🌈

const char *explain_errno_getc(int errnum, FILE *fp);

the explain_errno_getc function is used to obtain an explanation of an error returned by the getc(3) system call. the least the message will contain is the value of strerror(errnum), but usually it will do much better, and indicate the underlying cause in more detail. chef's kiss 🫶

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

int c = getc(fp);
if (c == EOF && ferror(fp))
{
    int err = errno;
    fprintf(stderr, "%s\n", explain_errno_getc(err, fp));
    exit(EXIT_FAILURE);
}

• 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. sneaky little things 💀
• fp — the original fp, exactly as passed to the getc(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. 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.

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🎀 explain_message_getc 🎀

void explain_message_getc(char *message, int message_size, FILE *fp);

the explain_message_getc function may be used to obtain an explanation of an error returned by the getc(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. periodt.

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:

int c = getc(fp);
if (c == EOF && ferror(fp))
{
    char message[3000];
    explain_message_getc(message, sizeof(message), fp);
    fprintf(stderr, "%s\n", message);
    exit(EXIT_FAILURE);
}

• message — the location in which to store the returned message. if a suitable message return buffer is supplied, this function is thread safe. slay 💅
• message_size — the size in bytes of the location in which to store the returned message.
• fp — the original fp, exactly as passed to the getc(3) system call.

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🧚 explain_message_errno_getc 🧚

void explain_message_errno_getc(char *message, int message_size, int
errnum, FILE *fp);

the explain_message_errno_getc function may be used to obtain an explanation of an error returned by the getc(3) system call. the least the message will contain is the value of strerror(errnum), but usually it will do much better, and indicate the underlying cause in more detail. main character energy tbh 👑

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

int c = getc(fp);
if (c == EOF && ferror(fp))
{
    int err = errno;
    char message[3000];
    explain_message_errno_getc(message, sizeof(message), err, fp);
    fprintf(stderr, "%s\n", message);
    exit(EXIT_FAILURE);
}

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

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💜 SEE ALSO 💜

• getc(3) — input of characters
• explain_getc_or_die(3) — input of characters and report errors

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👑 COPYRIGHT 👑

okay bestie here's the receipts, we're keeping it real and keeping it legal:

• libexplain version 1.4
• Copyright (C) 2008 Peter Miller

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and that's the whole page, babes 🌸 you just read explain_getc(3) from the Library Functions Manual, brought to you by libexplain version 1.4 with Copyright (C) 2008 Peter Miller — go explain some errors and live your truth 💖🦋✨