NAME
explain_timerfd_create - explain timerfd_create(2) errors
SYNOPSIS
#include <libexplain/timerfd_create.h>
const char *explain_timerfd_create(int clockid, int flags);
const char *explain_errno_timerfd_create(int errnum, int clockid, int
flags);
void explain_message_timerfd_create(char *message, int message_size,
int clockid, int flags);
void explain_message_errno_timerfd_create(char *message, int
message_size, int errnum, int clockid, int flags);
DESCRIPTION
These functions may be used to obtain explanations for errors returned
by the timerfd_create(2) system call.
explain_timerfd_create
const char *explain_timerfd_create(int clockid, int flags);
The explain_timerfd_create function is used to obtain an explanation of
an error returned by the timerfd_create(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.
clockid The original clockid, exactly as passed to the
timerfd_create(2) system call.
flags The original flags, exactly as passed to the timerfd_create(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 = timerfd_create(clockid, flags);
if (result < 0)
{
fprintf(stderr, "%s\n", explain_timerfd_create(clockid,
flags));
exit(EXIT_FAILURE);
}
The above code example is available pre-packaged as the
explain_timerfd_create_or_die(3) function.
explain_errno_timerfd_create
const char *explain_errno_timerfd_create(int errnum, int clockid, int
flags);
The explain_errno_timerfd_create function is used to obtain an
explanation of an error returned by the timerfd_create(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.
clockid The original clockid, exactly as passed to the
timerfd_create(2) system call.
flags The original flags, exactly as passed to the timerfd_create(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 = timerfd_create(clockid, flags);
if (result < 0)
{
int err = errno;
fprintf(stderr, "%s\n", explain_errno_timerfd_create(err,
clockid, flags));
exit(EXIT_FAILURE);
}
The above code example is available pre-packaged as the
explain_timerfd_create_or_die(3) function.
explain_message_timerfd_create
void explain_message_timerfd_create(char *message, int message_size,
int clockid, int flags);
The explain_message_timerfd_create function is used to obtain an
explanation of an error returned by the timerfd_create(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.
clockid The original clockid, exactly as passed to the
timerfd_create(2) system call.
flags The original flags, exactly as passed to the timerfd_create(2)
system call.
Example: This function is intended to be used in a fashion similar to
the following example:
int result = timerfd_create(clockid, flags);
if (result < 0)
{
char message[3000];
explain_message_timerfd_create(message, sizeof(message),
clockid, flags);
fprintf(stderr, "%s\n", message);
exit(EXIT_FAILURE);
}
The above code example is available pre-packaged as the
explain_timerfd_create_or_die(3) function.
explain_message_errno_timerfd_create
void explain_message_errno_timerfd_create(char *message, int
message_size, int errnum, int clockid, int flags);
The explain_message_errno_timerfd_create function is used to obtain an
explanation of an error returned by the timerfd_create(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.
clockid The original clockid, exactly as passed to the
timerfd_create(2) system call.
flags The original flags, exactly as passed to the timerfd_create(2)
system call.
Example: This function is intended to be used in a fashion similar to
the following example:
int result = timerfd_create(clockid, flags);
if (result < 0)
{
int err = errno;
char message[3000];
explain_message_errno_timerfd_create(message,
sizeof(message), err, clockid, flags);
fprintf(stderr, "%s\n", message);
exit(EXIT_FAILURE);
}
The above code example is available pre-packaged as the
explain_timerfd_create_or_die(3) function.
SEE ALSO
timerfd_create(2)
timers that notify via file descriptors
explain_timerfd_create_or_die(3)
timers that notify via file descriptors and report errors
COPYRIGHT
libexplain version 0.19
Copyright (C) 2009 Peter Miller
explain_timerfd_create(3)