86 lines
3.7 KiB
Bash
86 lines
3.7 KiB
Bash
# vim:ft=nroff
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cat <<EOF
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.TH TERMKEY_GETKEY 3
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.SH NAME
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termkey_getkey, termkey_getkey_force \- retrieve the next key event
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.SH SYNOPSIS
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.nf
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.B #include <termkey.h>
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.sp
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.BI "termkey_result termkey_getkey(termkey_t *" tk ", termkey_key *" key );
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.br
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.BI "termkey_result termkey_getkey_force(termkey_t *" tk ", termkey_key *" key );
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.fi
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.sp
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Link with \fI-ltermkey\fP.
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.SH DESCRIPTION
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\fBtermkey_getkey\fP attempts to retrieve a single keypress event from the buffer, and put it in the structure referred to by \fIkey\fP. If successful it will return \fBTERMKEY_RES_KEY\fP to indicate that the structure now contains a new keypress event. If nothing is in the buffer it will return \fBTERMKEY_RES_NONE\fP. If the buffer contains a partial keypress event which does not yet contain all the bytes required, it will return \fBTERMKEY_RES_AGAIN\fP. If no events are ready and the input stream is now closed, will return \fBTERMKEY_RES_EOF\fP.
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.PP
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\fBtermkey_getkey_force\fP is similar to \fBtermkey_getkey\fP but will not return \fBTERMKEY_RES_AGAIN\fP if a partial match is found. Instead, it will force an interpretation of the bytes, even if this means interpreting the start of an Escape-prefixed multi-byte sequence as a literal "Escape" key followed by normal letters.
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.PP
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Neither of these functions will block or perform any IO operations on the underlying filehandle. To use the instance in an asynchronous program, see \fBtermkey_advisereadable\fP(3). For a blocking call suitable for use in a synchronous program, use \fBtermkey_waitkey\fP(3) instead of \fBtermkey_getkey\fP().
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.PP
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The \fItermkey_key\fP structure is defined as follows:
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.PP
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.in +4n
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.nf
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typedef struct {
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termkey_type type;
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union {
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long codepoint; /* TERMKEY_TYPE_UNICODE */
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int number; /* TERMKEY_TYPE_FUNCTION */
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termkey_keysym sym; /* TERMKEY_TYPE_KEYSYM */
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} code;
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int modifiers;
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char utf8[7];
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} termkey_key;
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.fi
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.in
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.PP
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The \fItype\fP field indicates the type of event, and determines which of the members of the \fIcode\fP union is valid. It will be one of the following constants:
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.TP
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.B TERMKEY_TYPE_UNICODE
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a Unicode codepoint
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.TP
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.B TERMKEY_TYPE_FUNCTION
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a numbered function key
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.TP
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.B TERMKEY_TYPE_KEYSYM
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a symbolic key
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.PP
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The \fImodifiers\fP bitmask is composed of a bitwise-or of the constants \fBTERMKEY_KEYMOD_SHIFT\fP, \fBTERMKEY_KEYMOD_CTRL\fP and \fBTERMKEY_KEYMOD_ALT\fP.
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.PP
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The \fIutf8\fP field is only set on events whose \fItype\fP is \fBTERMKEY_TYPE_UNICODE\fP. It should not be read for other events.
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.PP
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To convert the \fIsym\fP to a symbolic name, see \fBtermkey_get_keyname\fP(3) function. It may instead be easier to convert the entire key event structure to a string, using \fBtermkey_snprint_key\fP(3).
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.SH "RETURN VALUE"
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\fBtermkey_getkey\fP() and \fBtermkey_getkey_force\fP() return one of the following constants:
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.TP
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.B TERMKEY_RES_NONE
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No key event is ready.
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.TP
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.B TERMKEY_RES_KEY
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A key event as been provided.
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.TP
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.B TERMKEY_RES_EOF
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No key events are ready and the terminal has been closed, so no more will arrive.
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.TP
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.B TERMKEY_RES_AGAIN
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No key event is ready yet, but a partial one has been found. This is only returned by \fBtermkey_getkey\fP(). To obtain the partial result even if it never completes, use \fBtermkey_getkey_force\fP().
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.SH EXAMPLE
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The following example program prints details of every keypress until the user presses "Ctrl-C". It demonstrates how to use the termkey instance in a typical \fBpoll\fP()-driven asynchronous program, which may include mixed IO with other file handles.
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.PP
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.in +4n
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`sed i.br demo-async.c`
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.in
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.nf
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.fi
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.SH "SEE ALSO"
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.BR termkey_new (3),
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.BR termkey_advisereadable (3),
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.BR termkey_waitkey (3),
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.BR termkey_set_waittime (3),
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.BR termkey_get_keyname (3),
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.BR termkey_snprint_key (3)
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EOF
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