explain_utime(3)

NAME
explain_utime - explain utime(2) errors

SYNOPSIS
#include <libexplain/utime.h>

const char *explain_utime(const char *pathname, const struct utimbuf *times);
const char *explain_errno_utime(int errnum, const char *pathname, const struct utimbuf *times);
void explain_message_utime(char *message, int message_size, const char *pathname, const struct utimbuf *times);
void explain_message_errno_utime(char *message, int message_size, int errnum, const char *pathname, const struct utimbuf *times);

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

  explain_utime
const char *explain_utime(const char *pathname, const struct utimbuf *times);

The explain_utime function is used to obtain an explanation of an error returned by the utime(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 (utime(pathname, times) < 0)
    {
        fprintf(stderr, "%s\n", explain_utime(pathname, times));
        exit(EXIT_FAILURE);
    }

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

times
    The original times, exactly as passed to the utime(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_utime
const char *explain_errno_utime(int errnum, const char *pathname, const struct utimbuf *times);

The explain_errno_utime function is used to obtain an explanation of an error returned by the utime(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 (utime(pathname, times) < 0)
    {
        int err = errno;
        fprintf(stderr, "%s\n", explain_errno_utime(err, pathname, times));
        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 utime(2) system call.

times
    The original times, exactly as passed to the utime(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_utime
void explain_message_utime(char *message, int message_size, const char *pathname, const struct utimbuf *times);

The explain_message_utime function may be used to obtain an explanation of an error returned by the utime(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 (utime(pathname, times) < 0)
    {
        char message[3000];
        explain_message_utime(message, sizeof(message), pathname, times);
        fprintf(stderr, "%s\n", message);
        exit(EXIT_FAILURE);
    }

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 utime(2) system call.

times
    The original times, exactly as passed to the utime(2) system call.

  explain_message_errno_utime
void explain_message_errno_utime(char *message, int message_size, int errnum, const char *pathname, const struct utimbuf *times);

The explain_message_errno_utime function may be used to obtain an explanation of an error returned by the utime(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 (utime(pathname, times) < 0)
    {
        int err = errno;
        char message[3000];
        explain_message_errno_utime(message, sizeof(message), err,
            pathname, times);
        fprintf(stderr, "%s\n", message);
        exit(EXIT_FAILURE);
    }

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 utime(2) system call.

times
    The original times, exactly as passed to the utime(2) system call.

SEE ALSO

utime(2)
    change file last access and modification times

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

COPYRIGHT
libexplain version
Copyright (C) 2008 Peter Miller