Scroll to navigation

explain_futimens(3) Library Functions Manual explain_futimens(3)

NAME

explain_futimens - explain futimens(3) errors

SYNOPSIS

#include <libexplain/futimens.h>

const char *explain_futimens(int fildes, const struct time_spec *data);
const char *explain_errno_futimens(int errnum, int fildes, const struct time_spec *data);
void explain_message_futimens(char *message, int message_size, int fildes, const struct time_spec *data);
void explain_message_errno_futimens(char *message, int message_size, int errnum, int fildes, const struct time_spec *data);

DESCRIPTION

These functions may be used to obtain explanations for errors returned by the futimens(3) system call.

explain_futimens

const char *explain_futimens(int fildes, const struct time_spec *data);

The explain_futimens function is used to obtain an explanation of an error returned by the futimens(3) 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.

The original fildes, exactly as passed to the futimens(3) system call.
The original data, exactly as passed to the futimens(3) system call.
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 (futimens(fildes, data) < 0)
{

fprintf(stderr, "%s\n", explain_futimens(fildes, data));

exit(EXIT_FAILURE); }

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

explain_errno_futimens

const char *explain_errno_futimens(int errnum, int fildes, const struct time_spec *data);

The explain_errno_futimens function is used to obtain an explanation of an error returned by the futimens(3) 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 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.
The original fildes, exactly as passed to the futimens(3) system call.
The original data, exactly as passed to the futimens(3) system call.
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 (futimens(fildes, data) < 0)
{

int err = errno;

fprintf(stderr, "%s\n", explain_errno_futimens(err, fildes, data));

exit(EXIT_FAILURE); }

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

explain_message_futimens

void explain_message_futimens(char *message, int message_size, int fildes, const struct time_spec *data);

The explain_message_futimens function is used to obtain an explanation of an error returned by the futimens(3) 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.

The location in which to store the returned message. If a suitable message return buffer is supplied, this function is thread safe.
The size in bytes of the location in which to store the returned message.
The original fildes, exactly as passed to the futimens(3) system call.
The original data, exactly as passed to the futimens(3) system call.

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


if (futimens(fildes, data) < 0)
{

char message[3000];
explain_message_futimens(message, sizeof(message), fildes, data);


fprintf(stderr, "%s\n", message);
exit(EXIT_FAILURE); }

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

explain_message_errno_futimens

void explain_message_errno_futimens(char *message, int message_size, int errnum, int fildes, const struct time_spec *data);

The explain_message_errno_futimens function is used to obtain an explanation of an error returned by the futimens(3) 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 location in which to store the returned message. If a suitable message return buffer is supplied, this function is thread safe.
The size in bytes of the location in which to store the returned message.
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.
The original fildes, exactly as passed to the futimens(3) system call.
The original data, exactly as passed to the futimens(3) system call.

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


if (futimens(fildes, data) < 0)
{

int err = errno;
char message[3000];
explain_message_errno_futimens(message, sizeof(message), err, fildes, data);


fprintf(stderr, "%s\n", message);
exit(EXIT_FAILURE); }

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

SEE ALSO

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

COPYRIGHT

libexplain version 1.4
Copyright (C) 2013 Peter Miller