explain_fchdir(3)

NAME
explain_fchdir - explain fchdir(2) errors

SYNOPSIS
#include <libexplain/fchdir.h>
const char *explain_fchdir(int fildes);
void explain_message_fchdir(char *message, int message_size, int fildes);
const char *explain_errno_fchdir(int errnum, int fildes);
void explain_message_errno_fchdir(char *message, int message_size, int errnum, int fildes);

DESCRIPTION
These functions may be used to obtain explanations for fchdir(2) errors.

  explain_fchdir
const char *explain_fchdir(int fildes);

The explain_fchdir function is used to obtain an explanation of an error returned by the fchdir(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.

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 (fchdir(fildes) < 0)
    {
        fprintf(stderr, '%s, explain_fchdir(fildes));
        exit(EXIT_FAILURE);
    }

fildes
    The original fildes, exactly as passed to the fchdir(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_fchdir
const char *explain_errno_fchdir(int errnum, int fildes);

The explain_errno_fchdir function is used to obtain an explanation of an error returned by the fchdir(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.

This function is intended to be used in a fashion similar to the following example:
    if (fchdir(fildes) < 0)
    {
        int err = errno;
        fprintf(stderr, '%s, explain_errno_fchdir(err, fildes));
        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.

fildes
    The original fildes, exactly as passed to the fchdir(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_fchdir
void explain_message_fchdir(char *message, int message_size, int fildes);

The explain_message_fchdir function is used to obtain an explanation of an error returned by the fchdir(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.

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 (fchdir(fildes) < 0)
    {
        char message[3000];
        explain_message_fchdir(message, sizeof(message), fildes);
        fprintf(stderr, '%s, message);
        exit(EXIT_FAILURE);
    }

message
    The location in which to store the returned message. Because a message return buffer has been supplied, this function is thread safe.

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

fildes
    The original fildes, exactly as passed to the fchdir(2) system call.

  explain_message_errno_fchdir
void explain_message_errno_fchdir(char *message, int message_size, int errnum, int fildes);

The explain_message_errno_fchdir function is used to obtain an explanation of an error returned by the fchdir(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.

This function is intended to be used in a fashion similar to the following example:
    if (fchdir(fildes) < 0)
    {
        int err = errno;
        char message[3000];
        explain_message_errno_fchdir(message, sizeof(message), err,
            fildes);
        fprintf(stderr, '%s, message);
        exit(EXIT_FAILURE);
    }

message
    The location in which to store the returned message. Because a message return buffer has been 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.

fildes
    The original fildes, exactly as passed to the fchdir(2) system call.

COPYRIGHT
libexplain version
Copyright (C) 2008 Peter Miller

AUTHOR
Written by Peter Miller <pmiller@opensource.org.au>