explain_adjtimex(3) Library Functions Manual explain_adjtimex(3)
NAME
explain_adjtimex - explain adjtimex(2) errors
SYNOPSIS
#include <libexplain/adjtimex.h>
const char *explain_adjtimex(struct timex *data);
const char *explain_errno_adjtimex(int errnum, struct timex *data);
void explain_message_adjtimex(char *message, int message_size, struct timex *data);
void explain_message_errno_adjtimex(char *message, int message_size, int errnum, struct timex *data);
DESCRIPTION
These functions may be used to obtain explanations for errors returned by the adjtimex(2) system call.
explain_adjtimex
const char *explain_adjtimex(struct timex *data);
The explain_adjtimex function is used to obtain an explanation of an error returned by the adjtimex(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.
data The original data, exactly as passed to the adjtimex(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:
int result = adjtimex(data);
if (result < 0)
{
fprintf(stderr, "%s
", explain_adjtimex(data));
exit(EXIT_FAILURE);
}
The above code example is available pre-packaged as the explain_adjtimex_or_die(3) function.
explain_errno_adjtimex
const char *explain_errno_adjtimex(int errnum, struct timex *data);
The explain_errno_adjtimex function is used to obtain an explanation of an error returned by the adjtimex(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 neces-
sary 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.
data The original data, exactly as passed to the adjtimex(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:
int result = adjtimex(data);
if (result < 0)
{
int err = errno;
fprintf(stderr, "%s
", explain_errno_adjtimex(err, data));
exit(EXIT_FAILURE);
}
The above code example is available pre-packaged as the explain_adjtimex_or_die(3) function.
explain_message_adjtimex
void explain_message_adjtimex(char *message, int message_size, struct timex *data);
The explain_message_adjtimex function is used to obtain an explanation of an error returned by the adjtimex(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.
data The original data, exactly as passed to the adjtimex(2) system call.
Example: This function is intended to be used in a fashion similar to the following example:
int result = adjtimex(data);
if (result < 0)
{
char message[3000];
explain_message_adjtimex(message, sizeof(message), data);
fprintf(stderr, "%s
", message);
exit(EXIT_FAILURE);
}
The above code example is available pre-packaged as the explain_adjtimex_or_die(3) function.
explain_message_errno_adjtimex
void explain_message_errno_adjtimex(char *message, int message_size, int errnum, struct timex *data);
The explain_message_errno_adjtimex function is used to obtain an explanation of an error returned by the adjtimex(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 neces-
sary 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.
data The original data, exactly as passed to the adjtimex(2) system call.
Example: This function is intended to be used in a fashion similar to the following example:
int result = adjtimex(data);
if (result < 0)
{
int err = errno;
char message[3000];
explain_message_errno_adjtimex(message, sizeof(message), err, data);
fprintf(stderr, "%s
", message);
exit(EXIT_FAILURE);
}
The above code example is available pre-packaged as the explain_adjtimex_or_die(3) function.
SEE ALSO
adjtimex(2)
tune kernel clock
explain_adjtimex_or_die(3)
tune kernel clock and report errors
COPYRIGHT
libexplain version 0.52
Copyright (C) 2009 Peter Miller
explain_adjtimex(3)