libxkbcommon 1.7.0
Macros | Typedefs | Enumerations | Functions
Keysyms

Macros

#define XKB_KEYSYM_MAX   0x1fffffff
 

Typedefs

typedef uint32_t xkb_keysym_t
 

Enumerations

enum  xkb_keysym_flags {
  XKB_KEYSYM_NO_FLAGS = 0 ,
  XKB_KEYSYM_CASE_INSENSITIVE = (1 << 0)
}
 

Functions

int xkb_keysym_get_name (xkb_keysym_t keysym, char *buffer, size_t size)
 
xkb_keysym_t xkb_keysym_from_name (const char *name, enum xkb_keysym_flags flags)
 
int xkb_keysym_to_utf8 (xkb_keysym_t keysym, char *buffer, size_t size)
 
uint32_t xkb_keysym_to_utf32 (xkb_keysym_t keysym)
 
xkb_keysym_t xkb_utf32_to_keysym (uint32_t ucs)
 
xkb_keysym_t xkb_keysym_to_upper (xkb_keysym_t ks)
 
xkb_keysym_t xkb_keysym_to_lower (xkb_keysym_t ks)
 

Detailed Description

Utility functions related to keysyms (short for “key symbols”).

Keysym Transformations

Keysym translation is subject to several "keysym transformations", as described in the XKB specification. These are: Each relevant function discusses which transformations it performs.These transformations are not applicable when a key produces multiple keysyms.

Macro Definition Documentation

◆ XKB_KEYSYM_MAX

#define XKB_KEYSYM_MAX   0x1fffffff

Maximum keysym value.

Since
1.6.0
See also
xkb_keysym_t

Typedef Documentation

◆ xkb_keysym_t

typedef uint32_t xkb_keysym_t

A number used to represent the symbols generated from a key on a keyboard.

A key, represented by a keycode, may generate different symbols according to keyboard state. For example, on a QWERTY keyboard, pressing the key labled <A> generates the symbol ‘a’. If the Shift key is held, it generates the symbol ‘A’. If a different layout is used, say Greek, it generates the symbol ‘α’. And so on.

Each such symbol is represented by a keysym (short for “key symbol”). Note that keysyms are somewhat more general, in that they can also represent some “function”, such as “Left” or “Right” for the arrow keys. For more information, see: Appendix A “KEYSYM Encoding” of the X Window System Protocol.

Specifically named keysyms can be found in the xkbcommon/xkbcommon-keysyms.h header file. Their name does not include the XKB_KEY_ prefix.

Besides those, any Unicode/ISO 10646 character in the range U+0100 to U+10FFFF can be represented by a keysym value in the range 0x01000100 to 0x0110FFFF. The name of Unicode keysyms is U<codepoint>, e.g. UA1B2.

The name of other unnamed keysyms is the hexadecimal representation of their value, e.g. 0xabcd1234.

Keysym names are case-sensitive.

Note
Encoding: Keysyms are 32-bit integers with the 3 most significant bits always set to zero. See: Appendix A “KEYSYM Encoding” of the X Window System Protocol.
See also
XKB_KEYSYM_MAX

Enumeration Type Documentation

◆ xkb_keysym_flags

Flags for xkb_keysym_from_name().

Enumerator
XKB_KEYSYM_NO_FLAGS 

Do not apply any flags.

XKB_KEYSYM_CASE_INSENSITIVE 

Find keysym by case-insensitive search.

Function Documentation

◆ xkb_keysym_get_name()

int xkb_keysym_get_name ( xkb_keysym_t keysym,
char * buffer,
size_t size )

Get the name of a keysym.

For a description of how keysyms are named, see xkb_keysym_t.

Parameters
[in]keysymThe keysym.
[out]bufferA string buffer to write the name into.
[in]sizeSize of the buffer.
Warning
If the buffer passed is too small, the string is truncated (though still NUL-terminated); a size of at least 64 bytes is recommended.
Returns
The number of bytes in the name, excluding the NUL byte. If the keysym is invalid, returns -1.

You may check if truncation has occurred by comparing the return value with the length of buffer, similarly to the snprintf(3) function.

See also
xkb_keysym_t

◆ xkb_keysym_from_name()

xkb_keysym_t xkb_keysym_from_name ( const char * name,
enum xkb_keysym_flags flags )

Get a keysym from its name.

Parameters
nameThe name of a keysym. See remarks in xkb_keysym_get_name(); this function will accept any name returned by that function.
flagsA set of flags controlling how the search is done. If invalid flags are passed, this will fail with XKB_KEY_NoSymbol.

If you use the XKB_KEYSYM_CASE_INSENSITIVE flag and two keysym names differ only by case, then the lower-case keysym name is returned. For instance, for KEY_a and KEY_A, this function would return KEY_a for the case-insensitive search. If this functionality is needed, it is recommended to first call this function without this flag; and if that fails, only then to try with this flag, while possibly warning the user he had misspelled the name, and might get wrong results.

Case folding is done according to the C locale; the current locale is not consulted.

Returns
The keysym. If the name is invalid, returns XKB_KEY_NoSymbol.
See also
xkb_keysym_t

◆ xkb_keysym_to_utf8()

int xkb_keysym_to_utf8 ( xkb_keysym_t keysym,
char * buffer,
size_t size )

Get the Unicode/UTF-8 representation of a keysym.

Parameters
[in]keysymThe keysym.
[out]bufferA buffer to write the UTF-8 string into.
[in]sizeThe size of buffer. Must be at least 7.
Returns
The number of bytes written to the buffer (including the terminating byte). If the keysym does not have a Unicode representation, returns 0. If the buffer is too small, returns -1.

This function does not perform any Keysym Transformations. Therefore, prefer to use xkb_state_key_get_utf8() if possible.

See also
xkb_state_key_get_utf8()

◆ xkb_keysym_to_utf32()

uint32_t xkb_keysym_to_utf32 ( xkb_keysym_t keysym)

Get the Unicode/UTF-32 representation of a keysym.

Returns
The Unicode/UTF-32 representation of keysym, which is also compatible with UCS-4. If the keysym does not have a Unicode representation, returns 0.

This function does not perform any Keysym Transformations. Therefore, prefer to use xkb_state_key_get_utf32() if possible.

See also
xkb_state_key_get_utf32()

◆ xkb_utf32_to_keysym()

xkb_keysym_t xkb_utf32_to_keysym ( uint32_t ucs)

Get the keysym corresponding to a Unicode/UTF-32 codepoint.

Returns
The keysym corresponding to the specified Unicode codepoint, or XKB_KEY_NoSymbol if there is none.

This function is the inverse of xkb_keysym_to_utf32. In cases where a single codepoint corresponds to multiple keysyms, returns the keysym with the lowest value.

Unicode codepoints which do not have a special (legacy) keysym encoding use a direct encoding scheme. These keysyms don't usually have an associated keysym constant (XKB_KEY_*).

For noncharacter Unicode codepoints and codepoints outside of the defined Unicode planes this function returns XKB_KEY_NoSymbol.

See also
xkb_keysym_to_utf32()
Since
1.0.0

◆ xkb_keysym_to_upper()

xkb_keysym_t xkb_keysym_to_upper ( xkb_keysym_t ks)

Convert a keysym to its uppercase form.

If there is no such form, the keysym is returned unchanged.

The conversion rules may be incomplete; prefer to work with the Unicode representation instead, when possible.

◆ xkb_keysym_to_lower()

xkb_keysym_t xkb_keysym_to_lower ( xkb_keysym_t ks)

Convert a keysym to its lowercase form.

The conversion rules may be incomplete; prefer to work with the Unicode representation instead, when possible.