NAME
XmbLookupString, XwcLookupString, Xutf8LookupString - obtain composed
input from an input method
SYNTAX
int XmbLookupString(XIC ic, XKeyPressedEvent *event, char
*buffer_return, int bytes_buffer, KeySym *keysym_return, Status
*status_return);
int XwcLookupString(XIC ic, XKeyPressedEvent *event, wchar_t
*buffer_return, int wchars_buffer, KeySym *keysym_return, Status
*status_return);
int Xutf8LookupString(XIC ic, XKeyPressedEvent *event, char
*buffer_return, int bytes_buffer, KeySym *keysym_return, Status
*status_return);
ARGUMENTS
buffer_return
Returns a multibyte string or wide character string (if any)
from the input method.
bytes_buffer
wchars_buffer
Specifies space available in the return buffer.
event Specifies the key event to be used.
ic Specifies the input context.
keysym_return
Returns the KeySym computed from the event if this argument
is not NULL.
status_return
Returns a value indicating what kind of data is returned.
DESCRIPTION
The XmbLookupString, XwcLookupString and Xutf8LookupString functions
return the string from the input method specified in the buffer_return
argument. If no string is returned, the buffer_return argument is
unchanged.
The KeySym into which the KeyCode from the event was mapped is returned
in the keysym_return argument if it is non-NULL and the status_return
argument indicates that a KeySym was returned. If both a string and a
KeySym are returned, the KeySym value does not necessarily correspond
to the string returned.
XmbLookupString and Xutf8LookupString return the length of the string
in bytes, and XwcLookupString returns the length of the string in
characters. Both XmbLookupString and XwcLookupString return text in
the encoding of the locale bound to the input method of the specified
input context, and Xutf8LookupString returns text in UTF-8 encoding.
Each string returned by XmbLookupString and XwcLookupString begins in
the initial state of the encoding of the locale (if the encoding of the
locale is state-dependent).
Note
®To ensure proper input processing, it is essential that the
client pass only KeyPress events to XmbLookupString,
XwcLookupString and Xutf8LookupString. Their behavior when a
client passes a KeyRelease event is undefined.
Clients should check the status_return argument before using the other
returned values. These three functions each return a value to
status_return that indicates what has been returned in the other
arguments. The possible values returned are:
XBufferOverflow The input string to be returned is too
large for the supplied buffer_return. The
required size (for XmbLookupString,
Xutf8LookupString in bytes; for
XwcLookupString in characters) is returned
as the value of the function, and the
contents of buffer_return and keysym_return
are not modified. The client should recall
the function with the same event and a
buffer of adequate size to obtain the
string.
XLookupNone No consistent input has been composed so
far. The contents of buffer_return and
keysym_return are not modified, and the
function returns zero.
XLookupChars Some input characters have been composed.
They are placed in the buffer_return
argument, using the encoding described
above, and the string length is returned as
the value of the function. The content of
the keysym_return argument is not modified.
XLookupKeySym A KeySym has been returned instead of a
string and is returned in keysym_return.
The content of the buffer_return argument
is not modified, and the function returns
zero.
XLookupBoth Both a KeySym and a string are returned;
XLookupChars and XLookupKeySym occur
simultaneously.
It does not make any difference if the input context passed as an
argument to XmbLookupString, XwcLookupString and Xutf8LookupString is
the one currently in possession of the focus or not. Input may have
been composed within an input context before it lost the focus, and
that input may be returned on subsequent calls to XmbLookupString,
XwcLookupString or Xutf8LookupString even though it does not have any
more keyboard focus.
The function Xutf8LookupString is an extension introduced by The
XFree86 Project, Inc. in their 4.0.2 release. Its presence is indicated
by the macro X_HAVE_UTF8_STRING.
SEE ALSO
XLookupKeysym(3), Compose(5)
Xlib - C Language X Interface