explain_tcflow(3) Library Functions Manual explain_tcflow(3)
NAME
explain_tcflow - explain tcflow(3) errors
SYNOPSIS
#include <libexplain/tcflow.h>
const char *explain_tcflow(int fildes, int action);
const char *explain_errno_tcflow(int errnum, int fildes, int action);
void explain_message_tcflow(char *message, int message_size, int fildes, int action);
void explain_message_errno_tcflow(char *message, int message_size, int errnum, int fildes, int action);
DESCRIPTION
These functions may be used to obtain explanations for errors returned by the tcflow(3) system call.
explain_tcflow
const char *explain_tcflow(int fildes, int action);
The explain_tcflow function is used to obtain an explanation of an error returned by the tcflow(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.
fildes The original fildes, exactly as passed to the tcflow(3) system call.
action The original action, exactly as passed to the tcflow(3) 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 (tcflow(fildes, action) < 0)
{
fprintf(stderr, "%s
", explain_tcflow(fildes, action));
exit(EXIT_FAILURE);
}
The above code example is available pre-packaged as the explain_tcflow_or_die(3) function.
explain_errno_tcflow
const char *explain_errno_tcflow(int errnum, int fildes, int action);
The explain_errno_tcflow function is used to obtain an explanation of an error returned by the tcflow(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.
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.
fildes The original fildes, exactly as passed to the tcflow(3) system call.
action The original action, exactly as passed to the tcflow(3) 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 (tcflow(fildes, action) < 0)
{
int err = errno;
fprintf(stderr, "%s
", explain_errno_tcflow(err, fildes, action));
exit(EXIT_FAILURE);
}
The above code example is available pre-packaged as the explain_tcflow_or_die(3) function.
explain_message_tcflow
void explain_message_tcflow(char *message, int message_size, int fildes, int action);
The explain_message_tcflow function is used to obtain an explanation of an error returned by the tcflow(3) system call. The least the mes-
sage 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.
fildes The original fildes, exactly as passed to the tcflow(3) system call.
action The original action, exactly as passed to the tcflow(3) system call.
Example: This function is intended to be used in a fashion similar to the following example:
if (tcflow(fildes, action) < 0)
{
char message[3000];
explain_message_tcflow(message, sizeof(message), fildes, action);
fprintf(stderr, "%s
", message);
exit(EXIT_FAILURE);
}
The above code example is available pre-packaged as the explain_tcflow_or_die(3) function.
explain_message_errno_tcflow
void explain_message_errno_tcflow(char *message, int message_size, int errnum, int fildes, int action);
The explain_message_errno_tcflow function is used to obtain an explanation of an error returned by the tcflow(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.
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.
fildes The original fildes, exactly as passed to the tcflow(3) system call.
action The original action, exactly as passed to the tcflow(3) system call.
Example: This function is intended to be used in a fashion similar to the following example:
if (tcflow(fildes, action) < 0)
{
int err = errno;
char message[3000];
explain_message_errno_tcflow(message, sizeof(message), err, fildes, action);
fprintf(stderr, "%s
", message);
exit(EXIT_FAILURE);
}
The above code example is available pre-packaged as the explain_tcflow_or_die(3) function.
SEE ALSO
tcflow(3)
terminal flow control
explain_tcflow_or_die(3)
terminal flow control and report errors
COPYRIGHT
libexplain version 0.52
Copyright (C) 2009 Peter Miller
explain_tcflow(3)