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