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1992-12-21
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(c) Copyright 1992 Commodore-Amiga, Inc. All rights reserved.
The information contained herein is subject to change without notice,
and is provided "as is" without warranty of any kind, either expressed
or implied. The entire risk as to the use of this information is
assumed by the user.
TABLE OF CONTENTS
asyncio/CloseAsync
asyncio/OpenAsync
asyncio/ReadAsync
asyncio/ReadAsyncChar
asyncio/WriteAsync
asyncio/WriteAsyncChar
asyncio/CloseAsync asyncio/CloseAsync
NAME
CloseAsync -- close an async io file.
SYNOPSIS
result = CloseAsync(file);
LONG CloseAsync(struct AsyncFile *);
FUNCTION
Closes a file, flushing any pending writes. Once this call has been
made, the file can no longer be accessed.
INPUTS
file - the file to close. May be NULL.
RESULT
result - < 0 for an error, >= 0 for success. Indicates whether closing
the file worked or not. If the file was opened in read-mode,
then this call will always work. In case of error,
dos.library/IoErr() can give more information.
SEE ALSO
OpenAsync, dos.library/Close()
asyncio/OpenAsync asyncio/OpenAsync
NAME
OpenAsync -- open a file for asynchronous IO.
SYNOPSIS
file = OpenAsync(fileName, accessMode, bufferSize);
struct AsyncFile OpenAsync(STRPTR, UBYTE, LONG);
FUNCTION
The named file is opened and an async file handle returned. If the
accessMode is MODE_READ, an existing file is opened for reading.
If the value is MODE_WRITE, a new file is created for writing. If
a file of the same name already exists, it is first deleted. If
accessMode is MODE_APPEND, an existing file is prepared for writing.
Data written is added to the end of the file. If the file does not
exists, it is created.
'fileName' is a filename and CANNOT be a simple device such as NIL:, a
window specification such as CON: or RAW:, or "*".
'bufferSize' specifies the size of the IO buffer to use. There are
in fact two buffers allocated, each of roughly (bufferSize/2) bytes
in size. The actual buffer size use can vary slightly as the size
is rounded to speed up DMA.
If the file cannot be opened for any reason, the value returned
will be NULL, and a secondary error code will be available by
calling the routine dos.library/IoErr().
INPUTS
name - name of the file to open
accessMode - one of MODE_READ, MODE_WRITE, or MODE_APPEND
bufferSize - size of IO buffer to use. 8192 is recommended as it
provides very good performance for relatively little
memory.
RESULTS
file - an async file handle or NULL for failure. You should not access
the fields in the AsyncFile structure, these are private to the
async IO routines. In case of failure, dos.library/IoErr() can
give more information.
SEE ALSO
CloseAsync(), dos.library/Open()
asyncio/ReadAsync asyncio/ReadAsync
NAME
ReadAsync -- read bytes from an async file.
SYNOPSIS
actualLength = ReadAsync(file,buffer,numBytes);
LONG ReadAsync(struct AsyncFile *file, APTR buffer, LONG numBytes);
FUNCTION
Read() reads bytes of information from an opened async file
into the buffer given. 'numBytes' is the number of bytes to read from
the file.
The value returned is the length of the information actually read.
So, when 'actualLength' is greater than zero, the value of
'actualLength' is the the number of characters read. Usually
ReadAsync() will try to fill up your buffer before returning. A value
of zero means that end-of-file has been reached. Errors are indicated
by a value of -1.
INPUTS
file - opened file to read, as obtained from OpenAsync()
buffer - buffer where to put bytes read
numBytes - number of bytes to read into buffer
RESULT
actualLength - actual number of bytes read, or -1 if an error. In
case of error, dos.library/IoErr() can give more
information.
SEE ALSO
OpenAsync(), CloseAsync(), WriteAsync(), ReadCharAsync(),
dos.library/Read()
asyncio/ReadCharAsync asyncio/ReadCharAsync
NAME
ReadCharAsync -- read a single byte from an async file.
SYNOPSIS
byte = ReadCharAsync(file);
LONG ReadCharAsync(struct AsyncFile *file);
FUNCTION
This function reads a single byte from an async file. The byte is
returned, or -1 if there was an error reading, or if the end-of-file
was reached.
INPUTS
file - opened file to read from, as obtained from OpenAsync()
RESULT
byte - the byte read, or -1 if no byte was read. In case of error,
dos.library/IoErr() can give more information.
SEE ALSO
OpenAsync(), CloseAsync(), WriteCharAsync(), ReadAsync()
dos.library/Read()
asyncio/WriteAsync asyncio/WriteAsync
NAME
WriteAsync -- write data to an async file.
SYNOPSIS
actualLength = WriteAsync(file,buffer,numBytes);
LONG WriteAsync(struct AsyncFile *file, APTR buffer, LONG numBytes);
FUNCTION
WriteAsync() writes bytes of data to an opened async file. 'numBytes'
indicates the number of bytes of data to be transferred. 'buffer'
points to the data to write. The value returned is the length of
information actually written. So, when 'numBytes' is greater than
zero, the value of 'numBytes' is the number of characters written.
Errors are indicated by a value of -1.
INPUTS
file - an opened file, as obtained from OpenAsync()
buffer - address of data to write
numBytes - number of bytes to write to the file
RESULT
actualLength - number of bytes written, or -1 if error. In case
of error, dos.library/IoErr() can give more
information.
SEE ALSO
OpenAsync(), CloseAsync(), ReadAsync(), WriteCharAsync(),
dos.library/Write
asyncio/WriteCharAsync asyncio/WriteCharAsync
NAME
WriteCharAsync -- write a single byte to an async file.
SYNOPSIS
result = WriteCharAsync(file,byte);
LONG WriteCharAsync(struct AsyncFile *, UBYTE byte);
FUNCTION
This function write a single byte to an async file.
INPUTS
file - an opened async file, as obtained from OpenAsync()
byte - byte of data to add to the file
RESULT
result - 1 if the byte was written, -1 if there was an error. In
case of error, dos.library/IoErr() can give more information.
SEE ALSO
OpenAsync(), CloseAsync(), ReadAsync(), WriteCharAsync(),
dos.library/Write