I’ve been working on a window manager and I’ve just started thinking about how to handle multiple monitor setups. I did some research on whether to use Xinerama or XRandr, and eventually decided on using XRandr, however I can not find any documentation whatsoever on how to use the XRandr header file, besides the header file on my computer (<X11/extensions/Xrandr.h>) and this StackOverflow question.
I’ve tried googling some of the function’s names and simple terms like "XRandr documentation" but all I find is man pages for the command line tool, more header files, or this doc which doesn’t explain how to use it.
Could anybody find me a relevant doc page for this header? Thanks in advance.
>Solution :
There’s a man 3 Xrandr.
Quick redundant excerpt:
Functions
There are two classes of interfaces: those which can be safely called
even if RandR is not implemented on a screen (to make common idioms
not dependent on the server having support), and those which will
return errors if the extension is not present.XRRRotations returns both the possible set of rotations/reflections
supported (as a bitmask) as the value of the function, along with the
current rotation/reflection of the screen.XRRSizes returns the size and a pointer to the current sizes supported
by the specified screen. The first size specified is the default size
of the server. If RandR is not supported, it returns 0 for the number
of sizes.XRRRates returns a pointer to the rates supported by the specified
size. If RandR is not supported, it returns 0 for the number of rates.XRRTimes returns the time last reported by the server along with the
timestamp the last configuration changed. If the configuration has
changed since the client last updated its view of the server time,
requests to change the configuration will fail until the client has an
up to date timestamp.XRRRootToScreen returns the screen number given a root window (for
example, from an XRRScreenChangeNotifyEvent).The rest of the functions will fail if applied to screens not
implementing the RandR extension. XRRSetScreenConfig sets the screen
size and rotation and reflection to the desired values on the screen
specified by draw, or returns a BadValue error. size_index specifies
which size configuration is to be used, rotation specifies which
rotation or reflection is to be used (or a BadValue error is
returned). The timestamp is used by the server to make sure the client
has up to date configuration information. Status is returned to
indicate success or failure; a client must refresh its configuration
information if it fails and try the call again (by calling
XRRGetScreenInfo).XRRSetScreenConfigAndRate is like XRRSetScreenConfig but also sets the
refresh rate. If specified rate is not supported a BadValue error is
returned.XRRConfigRotations, XRRConfigSizes, XRRConfigCurrentConfiguration,
XRRConfigTimes, XRRConfigRates, and XRRConfigCurrentRate are used to
get specific configuration information out of a screen configuration.XRRGetScreenInfo returns a screen configuration for later use; the
information is private to the library. Call XRRFreeScreenConfigInfo to
free this information when you are finished with it. It forces a round
trip to the server.Other functions include: XRRQueryExtension which returns the event and
error base codes, XRRQueryVersion , which returns the current version
of the extension (this information is cached by the library).