explain_opendir(3)

NAME
explain_opendir - explain opendir(3) errors

SYNOPSIS
const char *explain_opendir(const char *pathname);
const char *explain_errno_opendir(int errnum, const char *pathname); int errnum, const char *pathname);
void explain_message_opendir(char *message, int message_size,
void explain_message_errno_opendir(char *message, int message_size, const char *pathname);

DESCRIPTION
These functions may be used to explain opendir(3) errors.

  explain_opendir
const char *explain_opendir(const char *pathname);

The explain_opendir function is used to obtain an explanation of an error returned by the opendir(3) function. 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:
    DIR *dp = opendir(pathname);
    if (!dp)
    {
        fprintf(stderr, "%s\n", explain_opendir(pathname));
        exit(EXIT_FAILURE);
    }

pathname
    The original pathname, exactly as passed to the opendir(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.

  explain_errno_opendir
const char *explain_errno_opendir(int errnum, const char *pathname); int errnum, const char *pathname);

The explain_errno_opendir function is used to obtain an explanation of an error returned by the opendir(3) function. 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:
    DIR *dp = opendir(pathname);
    if (!dp)
    {
        int errnum = errno;
        const char *message = explain_errno_opendir(errnum, pathname);
        fprintf(stderr, "%s\n", message);
        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.

pathname
    The original pathname, exactly as passed to the opendir(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.

  explain_message_opendir
void explain_message_opendir(char *message, int message_size, const char *pathname);

The explain_message_opendir function is used to obtain an explanation of an error returned by the opendir(3) function. 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:
    DIR *dp = opendir(pathname);
    if (!dp)
    {
        char message[3000];
        explain_message_opendir(message, sizeof(message), pathname);
        fprintf(stderr, "%s\n", 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 if the buffer is thread safe.

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

pathname
    The original pathname, exactly as passed to the opendir(3) system call.

  explain_message_errno_opendir
void explain_message_errno_opendir(char *message, int message_size, const char *pathname);

The explain_message_errno_opendir function is used to obtain an explanation of an error returned by the opendir(3) function. 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:
    DIR *dp = opendir(pathname);
    if (!dp);
    {
        int err = errno;
        char message[3000];
        explain_message_errno_opendir(message, sizeof(message), err,
            pathname);
        fprintf(stderr, '%s\n', 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 if the buffer 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.

pathname
    The original pathname, exactly as passed to the opendir(3) system call.

COPYRIGHT
libexplain version
Copyright (C) 2008 Peter Miller

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