explain_utimensat(3)

NAME
explain_utimensat - explain utimensat(2) errors

SYNOPSIS
#include <libexplain/utimensat.h>

const char *explain_utimensat(int fildes, const char *pathname, const struct timespec *data, int flags);
const char *explain_errno_utimensat(int errnum, int fildes, const char *pathname, const struct timespec *data, int flags);
void explain_message_utimensat(char *message, int message_size, int fildes, const char *pathname, const struct timespec *data, int flags);
void explain_message_errno_utimensat(char *message, int message_size, int errnum, int fildes, const char *pathname, const struct timespec *data, int flags);

DESCRIPTION
These functions may be used to obtain explanations for errors returned by the utimensat(2) system call.

  explain_utimensat
const char *explain_utimensat(int fildes, const char *pathname, const struct timespec *data, int flags);

The explain_utimensat function is used to obtain an explanation of an error returned by the utimensat(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.

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

pathname
    The original pathname, exactly as passed to the utimensat(2) system call.

data
    The original data, exactly as passed to the utimensat(2) system call.

flags
    The original flags, exactly as passed to the utimensat(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.

Example: This function is intended to be used in a fashion similar to the following example:
    if (utimensat(fildes, pathname, data, flags) < 0)
    {
    fprintf(stderr, "%s\n", explain_utimensat(fildes, pathname, data, flags));
        exit(EXIT_FAILURE);
    }

The above code example is available pre-packaged as the explain_utimensat_or_die(3) function.

  explain_errno_utimensat
const char *explain_errno_utimensat(int errnum, int fildes, const char *pathname, const struct timespec *data, int flags);

The explain_errno_utimensat function is used to obtain an explanation of an error returned by the utimensat(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.

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 utimensat(2) system call.

pathname
    The original pathname, exactly as passed to the utimensat(2) system call.

data
    The original data, exactly as passed to the utimensat(2) system call.

flags
    The original flags, exactly as passed to the utimensat(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.

Example: This function is intended to be used in a fashion similar to the following example:
    if (utimensat(fildes, pathname, data, flags) < 0)
    {
        int err = errno;
    fprintf(stderr, "%s\n", explain_errno_utimensat(err, fildes, pathname, data, flags));
        exit(EXIT_FAILURE);
    }

The above code example is available pre-packaged as the explain_utimensat_or_die(3) function.

  explain_message_utimensat
void explain_message_utimensat(char *message, int message_size, int fildes, const char *pathname, const struct timespec *data, int flags);

The explain_message_utimensat function is used to obtain an explanation of an error returned by the utimensat(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.

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.

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

pathname
    The original pathname, exactly as passed to the utimensat(2) system call.

data
    The original data, exactly as passed to the utimensat(2) system call.

flags
    The original flags, exactly as passed to the utimensat(2) system call.

Example: This function is intended to be used in a fashion similar to the following example:
    if (utimensat(fildes, pathname, data, flags) < 0)
    {
        char message[3000];
    explain_message_utimensat(message, sizeof(message), fildes, pathname, data, flags);
        fprintf(stderr, "%s\n", message);
        exit(EXIT_FAILURE);
    }

The above code example is available pre-packaged as the explain_utimensat_or_die(3) function.

  explain_message_errno_utimensat
void explain_message_errno_utimensat(char *message, int message_size, int errnum, int fildes, const char *pathname, const struct timespec *data, int flags);

The explain_message_errno_utimensat function is used to obtain an explanation of an error returned by the utimensat(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.

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.

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

pathname
    The original pathname, exactly as passed to the utimensat(2) system call.

data
    The original data, exactly as passed to the utimensat(2) system call.

flags
    The original flags, exactly as passed to the utimensat(2) system call.

Example: This function is intended to be used in a fashion similar to the following example:
    if (utimensat(fildes, pathname, data, flags) < 0)
    {
        int err = errno;
        char message[3000];
    explain_message_errno_utimensat(message, sizeof(message), err, fildes, pathname, data, flags);
        fprintf(stderr, "%s\n", message);
        exit(EXIT_FAILURE);
    }

The above code example is available pre-packaged as the explain_utimensat_or_die(3) function.

SEE ALSO

utimensat(2)
    change file timestamps with nanosecond precision

explain_utimensat_or_die(3)
    change file timestamps with nanosecond precision and report errors

COPYRIGHT
libexplain version 1.1
Copyright (C) 2012 Peter Miller