explain_utimens(3)

NAME
explain_utimens - explain utimens(2) errors

SYNOPSIS
#include <libexplain/utimens.h>

const char *explain_utimens(const char *pathname, const struct timespec *data);
const char *explain_errno_utimens(int errnum, const char *pathname, const struct timespec *data);
void explain_message_utimens(char *message, int message_size, const char *pathname, const struct timespec *data);
void explain_message_errno_utimens(char *message, int message_size, int errnum, const char *pathname, const struct timespec *data);

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

  explain_utimens
const char *explain_utimens(const char *pathname, const struct timespec *data);

The explain_utimens function is used to obtain an explanation of an error returned by the utimens(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.

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

data
    The original data, exactly as passed to the utimens(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 (utimens(pathname, data) < 0)
    {
    fprintf(stderr, "%s\n", explain_utimens(pathname, data));
        exit(EXIT_FAILURE);
    }

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

  explain_errno_utimens
const char *explain_errno_utimens(int errnum, const char *pathname, const struct timespec *data);

The explain_errno_utimens function is used to obtain an explanation of an error returned by the utimens(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.

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

data
    The original data, exactly as passed to the utimens(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 (utimens(pathname, data) < 0)
    {
        int err = errno;
    fprintf(stderr, "%s\n", explain_errno_utimens(err, pathname, data));
        exit(EXIT_FAILURE);
    }

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

  explain_message_utimens
void explain_message_utimens(char *message, int message_size, const char *pathname, const struct timespec *data);

The explain_message_utimens function is used to obtain an explanation of an error returned by the utimens(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.

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

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

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

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

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

The explain_message_errno_utimens function is used to obtain an explanation of an error returned by the utimens(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.

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

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

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

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

SEE ALSO

utimens(2)
    change file last access and modification times

explain_utimens_or_die(3)
    change file last access and modification times and report errors

COPYRIGHT
libexplain version 1.4
Copyright (C) 2012 Peter Miller