explain_dup2(3)

💖 explain_dup2(3) — Library Functions Manual 💖

okay bestie, so this is explain_dup2(3) from the libexplain crew, and it's literally here to tell you why your dup2(2) call said no. 🫶

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✨ NAME ✨

explain_dup2 — explain dup2(2) errors

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🌸 SYNOPSIS 🌸

#include <libexplain/dup2.h>
const char *explain_dup2(int oldfd, int newfd);
const char *explain_errno_dup2(int errnum, int oldfd, int newfd);
void explain_message_dup2(char *message, int message_size, int oldfd,
int newfd);
void explain_message_errno_dup2(char *message, int message_size, int
errnum, int oldfd, int newfd);

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🦋 DESCRIPTION 🦋

These functions may be used to obtain explanations for errors returned by the dup2(2) system call. no cap, that's the whole vibe. 💅

🌈 explain_dup2

const char *explain_dup2(int oldfd, int newfd);

The explain_dup2 function is used to obtain an explanation of an error returned by the dup2(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. it's giving detective energy 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:

if (dup2(oldfd, newfd) < 0)
{
    fprintf(stderr, "%s\n", explain_dup2(oldfd, newfd));
    exit(EXIT_FAILURE);
}

• oldfd — The original oldfd, exactly as passed to the dup2(2) system call.
• newfd — The original newfd, exactly as passed to the dup2(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.

🎀 explain_errno_dup2

const char *explain_errno_dup2(int errnum, int oldfd, int newfd);

The explain_errno_dup2 function is used to obtain an explanation of an error returned by the dup2(2) 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. she's thorough, okay? 💅

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

if (dup2(oldfd, newfd) < 0)
{
    int err = errno;
    fprintf(stderr, "%s\n", explain_errno_dup2(err, oldfd, newfd));
    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. 👀
• oldfd — The original oldfd, exactly as passed to the dup2(2) system call.
• newfd — The original newfd, exactly as passed to the dup2(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.

🧚 explain_message_dup2

void explain_message_dup2(char *message, int message_size, int oldfd,
int newfd);

The explain_message_dup2 function may be used to obtain an explanation of an error returned by the dup2(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. iconic behaviour honestly. ✨

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 (dup2(oldfd, newfd) < 0)
{
    char message[3000];
    explain_message_dup2(message, sizeof(message), oldfd, newfd);
    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.
• oldfd — The original oldfd, exactly as passed to the dup2(2) system call.
• newfd — The original newfd, exactly as passed to the dup2(2) system call.

💜 explain_message_errno_dup2

void explain_message_errno_dup2(char *message, int message_size, int
errnum, int oldfd, int newfd);

The explain_message_errno_dup2 function may be used to obtain an explanation of an error returned by the dup2(2) 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. the way she just knows things. 🔥

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

if (dup2(oldfd, newfd) < 0)
{
    int err = errno;
    char message[3000];
    explain_message_errno_dup2(message, sizeof(message), err, oldfd, newfd);
    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. 🙈
• oldfd — The original oldfd, exactly as passed to the dup2(2) system call.
• newfd — The original newfd, exactly as passed to the dup2(2) system call.

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👑 SEE ALSO 👑

• dup2(2) — duplicate a file descriptor
• explain_dup2_or_die(3) — duplicate a file descriptor and report errors

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💖 COPYRIGHT 💖

libexplain version 1.4

Copyright (C) 2008 Peter Miller

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and that's the whole page bestie!! 🌟 this was libexplain version 1.4, copyrighted 2008 by Peter Miller, and yes we're still obsessed with her. go forth and dup2 responsibly. periodt. 💅✨🦋