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─────Run-Time Library───────────────────────────────────────────────────────
 
     The _fwopen function is a high-level call that opens a new
     QuickWin window, returning a file-stream pointer. This routine is
     used only in QuickWin programs; it is not part of the Windows
     API. For full details about QuickWin, see Chapter 8 of the
     Programming Techniques manual.
 
     The _wopeninfo and _wsizeinfo structures, declared in STDIO.H,
     are used to pass window initialization information, including the
     window's initial size and position on the screen. You can pass
     NULL for these arguments to accept QuickWin defaults or declare
     variables of these two structure types and fill in their fields.
 
     If you declare _wopeninfo and _wsizeinfo variables, assign the
     _QWINVER macro to the _version field. _QWINVER is the current
     QuickWin version and is defined in STDIO.H and IO.H.
 
     For the _wopeninfo variable, assign a null-terminated string to
     the _title field containing the desired window title. You can
     also optionally set the size of the window's screen buffer in the
     _wbufsize field. The default is 2048 bytes, but you can pass some
     other number or the value _WINBUFINF. This causes the buffer to
     be reallocated continually so that all window output is retained
     for scrolling.
 
     For the _wsizeinfo variable, assign one of the following values
     to the _type field:
 
     Value            Meaning
 
     _WINSIZEMIN      Minimize the window
     _WINSIZEMAX      Maximize the window
     _WINSIZECHAR     Use character coordinates for the window size
 
     If the type is _WINSIZECHAR, you must supply the _x, _y, _h, and
     _w values in the remainder of the structure. They specify the
     upper-left corner and the height and width of the window (in
     characters).
 
     The <mode> parameter is a pointer to the stream I/O mode. The
     _fwopen function accepts the same mode values as the STDIO.H
     fopen function:
 
     Type     Description
 
     "r"      Opens for reading
     "w"      Opens for writing
     "r+"     Opens for both reading and writing
     "w+"     Opens for both reading and writing
 
     In addition to the values listed above, one of the following
     characters can be included in <mode> to specify the translation
     mode for newline characters:
 
     Mode     Meaning
 
     "t"      Open in text (translated) mode
     "b"      Open in binary (untranslated) mode
 
     If "t" or "b" is not given in <mode>, the translation mode is
     defined by the default-mode variable _fmode. If "t" or "b" is
     prefixed to the argument, the function fails and returns NULL.
 
     If _fwopen is successful, the returned stream can be passed to
     standard STDIO.H functions such as fread, fwrite, and fprintf. If
     you write to a stream and then read from it, or if you read from
     a stream and then write to it, call the STDIO.H rewind function
     between the I/O calls. To close an open window stream, call the
     STDIO.H function fclose. If you have opened a window with
     _fwopen, you can use the _fileno macro to obtain a file handle,
     which you can then pass to other QuickWin calls, such as
     _wsetscreenbuf or _wsetsize.
 
     Return Value
 
     If successful, the _fwopen function returns a stream pointer
     (FILE *) to the new window. A return value of NULL indicates an
     error.
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