|o||If the specified property does not exist for the specified device, XIGetProperty returns None to actual_type_return and the value zero to actual_format_return and bytes_after_return. The nitems_return argument is empty. In this case, the delete argument is ignored.|
o If the specified property exists but its type does not match the specified type, XIGetProperty returns the actual property type to actual_type_return, the actual property format (never zero) to actual_format_return, and the property length in bytes (even if the actual_format_return is 16 or 32) to bytes_after_return. It also ignores the delete argument. The nitems_return argument is empty.
o If the specified property exists and either you assign XIAnyPropertyType to the req_type argument or the specified type matches the actual property type, XIGetProperty returns the actual property type to actual_type_return and the actual property format (never zero) to actual_format_return. It also returns a value to bytes_after_return and nitems_return, by defining the following values:
N = length of the stored property in bytes I = 4 * offset T = N - I L = MINIMUM(T, 4 * length) A = N - (I + L)
The returned value starts at byte index I in the property (indexing from zero), and its length in bytes is L. If the value for long_offset causes L to be negative, a BadValue error results. The value of bytes_after_return is A, giving the number of trailing unread bytes in the stored property.
If the returned format is 8, the returned data is represented as a char array. If the returned format is 16, the returned data is represented as a uint16_t array and should be cast to that type to obtain the ele- ments. If the returned format is 32, the returned data is represented as a uint32_t array and should be cast to that type to obtain the elements.
XIGetProperty always allocates one extra byte in prop_return (even if the property is zero length) and sets it to zero so that simple properties consisting of characters do not have to be copied into yet another string before use.
If delete is True and bytes_after_return is zero, XIGetProperty deletes the property from the window and generates an XIPropertyNotify event on the window.
The function returns Success if it executes successfully. To free the resulting data, use XFree.
XIGetProperty can generate BadAtom, BadValue, and BadWindow errors.
The XIChangeProperty function alters the property for the specified device and causes the X server to generate a XIPropertyNotify event for that device. XIChangeProperty performs the following:
o If mode is XIPropModeReplace, XIChangeProperty discards the previous property value and stores the new data.
o If mode is XIPropModePrepend or XIPropModeAppend, XIChangeProperty inserts the specified data before the beginning of the existing data or onto the end of the existing data, respectively. The type and format must match the existing property value, or a BadMatch error results. If the property is undefined, it is treated as defined with the correct type and format with zero-length data.
If the specified format is 8, the property data must be a char array. If the specified format is 16, the property data must be a uint16_t array. If the specified format is 32, the property data must be a uint32_t array.
The lifetime of a property is not tied to the storing client. Properties remain until explicitly deleted, until the device is removed, or until the server resets. The maximum size of a property is server dependent and can vary dynamically depending on the amount of memory the server has available. (If there is insufficient space, a BadAlloc error results.)
XIChangeProperty can generate BadAlloc, BadAtom, BadMatch, BadValue, and BadDevice errors.
The XIDeleteProperty function deletes the specified property only if the property was defined on the specified device and causes the X server to generate a XIPropertyNotify event for the device unless the property does not exist.
XIDeleteProperty can generate BadAtom and BadDevice errors.
BadAlloc The server failed to allocate the requested resource or server memory.
BadAtom A value for an Atom argument does not name a defined Atom.
BadValue Some numeric value falls outside the range of values accepted by the request. Unless a specific range is specified for an argument, the full range defined by the arguments type is accepted. Any argument defined as a set of alternatives can generate this error.
BadDevice An invalid device was specified. The device does not exist.
BadAtom An invalid property was specified. The property does not exist.
The protocol headers for XI 2.0 did not provide XIAnyPropertyType, XIPropModeReplace, XIPropModePrepend or XIPropModeAppend. Use AnyPropertyType, PropModeReplace, PropModePrepend and PropModeAppend instead, respectively.