giiSplitInputs(3) Open, join, split and close inputs

Other Alias

giiOpen, giiJoinInputs, giiClose


#include <ggi/gii.h>
gii_input_t giiOpen(const char * input, ...);
gii_input_t giiJoinInputs(gii_input_t inp, gii_input_t inp2);
int giiSplitInputs(gii_input_t inp, gii_input_t *newhand,
uint32_t origin, uint32_t flags);
int giiClose(gii_input_t inp);


giiOpen opens an input. This function is given the name of an input driver to load. Passing NULL here results in an auto-select mechanism, which currently means examining the contents of GII_INPUT.

The optional arguments are a NULL-terminated list of pointers, which are used to give additional information to the targets. Currently only the first pointer is specified: void * argptr, a pointer to a library-specific struct. It is used to pass parameters that are not easily transferable in textual form.

Parameters which can be represented in text format are usually transfered in the input parameter, in the format: library_name:arguments

giiJoinInputs joins two inputs into one. From a programmers' point of view, this closes both inp and inp2 and opens an new input that combines both inputs into one. That is, after giiJoinInputs has completed, there is no need to giiClose inp and inp2 any more. When cleaning up, you need to close the returned input instead. See the example for details. However the inputs are not actually closed or reopened internally. That is, you will not get any startup-events or similar the driver generates, though pending events of both old inputs are transferred to the newly created input.

giiSplitInputs splits one of the inputs from a group of joined inputs and returns the handle. The parameter origin can be used to choose which input to detach (use GGI_EV_ORIGIN_NONE to match any input.) The detached handle is returned in newhand. Note, though, that if the detached input is the same one given in inp, then the handle returned in newhand will be that of the rest of the joined inputs instead. You can tell whether this happened by checking the return code. Events queued in the joined input for the newly split input are not transferred automatically. You must drain them out yourself. The parameter flags is reserved for future use and should be set to 0.

giiClose releases and destroys an open input and its associated internal control structures. This will put back input streams to their default modes, etc.

Important: If you want to handle input while also using LibGGI, using LibGII functions such as giiOpen is almost certainly not what you want. Use LibGGI functions such as ggiEventRead(3) with the LibGGI visual instead.


giiOpen and giiJoinInputs return the opened or joined input, or NULL for error. The gii_input_t type is opaque to the programmer and can only be used through GII functions.

giiClose returns GGI_OK (== 0) on success, otherwise an gii-error(3) code.

giiSplitInputs returns 0 for normal success, or 1 if the input which was split off was the same as the one passed in inp (in which case, newhand may contain a handle to a joined set of visuals.) Otherwise, it returns an gii-error(3) code.


GII input management:

gii_input_t inp, inp2, inp3;
/* Initialize the GII library. This must be called before any other
 * GII function. */
if (giiInit() != 0) exit(1);
/* Open the nulldevice for testing ... */
if ((inp=giiOpen("input-null",NULL)) == NULL) {
/* Open stdin for testing ... */
if ((inp2=giiOpen("input-stdin",NULL)) == NULL) {
/* Open evdev for testing ... */
if ((inp3=giiOpen("input-linux-evdev",NULL)) == NULL) {
/* Now join them. Note the usage of _i_n_p_=_giiJoin(inp,inp2);
 * This is the recommended way to do this. */
/* Note that this mends inp2 into inp. That is you may not call
   giiClose(inp2) - this happens together with giiClose(inp) ! */
/* Join another */
/* ... do the real work here ... */
/* Split one of them back out of the join. */
res = ggiSplitInputs(inp, &inp2, GII_EV_ORIGIN_NONE, 0);
if (res == 1) {
    gii_input_t tmp;
    tmp = imp2;
    imp2 = imp1;
    imp1 = tmp;
else if (res < 0) fprintf(stderr, "Failed to split inputs\n");
/* Close the single input */
/* Close the joined input */
/* Now close down LibGII. */