cdk_binding (3) Linux Manual Page

NAME

cdk_binding – Curses Development Kit Character Binding Capabilities.

SYNOPSIS

cc [ flag … ] file … -lcdk [ library … ]

#include <cdk.h>

void bindCDKObject(
    EObjectType cdkType,
    void *object,
    chtype key,
    BINDFN function,
    void *data);
int checkCDKObjectBind(
    EObjectType cdkType,
    void *object,
    chtype key);
void cleanCDKObjectBindings(
    EObjectType cdkType,
    void *object);
bool isCDKObjectBind(
    EObjectType cdkType,
    void *object,
    chtype key);
void unbindCDKObject(
    EObjectType cdkType,
    void *object,
    chtype key);
int getcCDKObject(
    CDKOBJS *object);
int getchCDKObject(
    CDKOBJS *object,
    boolean *functionKey);

DESCRIPTION

Cdk has the ability to create user definable key bindings. This ability makes Cdk more dynamic and usable for a wide variety of tasks. The following section outlines the binding functions, their use, and their purpose.

bindCDKObject

creates a key binding between a specific Cdk widget (object) given key (key). The parameter cdkType is of type EObjectType which is one of the following values.

The parameter function is the callback function. The parameter data points to data passed to the callback function. The parameter key is the key hit which triggered this callback.

checkCDKObjectBind

check to see if a binding for the given key exists. If it does, Cdk runs the associated command and returns its value, normally TRUE. If no binding exists, return FALSE.

The widgets which accept input, e.g., via "inject" methods, use this to check if the injected character is bound to a function. If that returns TRUE, the widget may update its exitType value: if earlyExit value is set (not equal to vNEVER_ACTIVATED), the widget sets exitType to that value.

cleanCDKObjectBindings

removes all user defined key bindings from the given widget.

isCDKObjectBind

check to see if a binding for the given key exists. If it does return TRUE. If no binding exists, return FALSE.

unbindCDKObject

removes a specific binding to an object. The parameter are the same as for bindCDKObject.

getcCDKObject

reads a keycode from the given widget. This is depcrecated: use getchCDKObject.

getchCDKObject

reads a keycode from the given widget. It sets a flag to indicate if the result is a function key. If the keycode has been bound to the special function getcCDKBind, then it will be translated to the value which was given for the binding data. Otherwise, a few special cases are performed:

Key	Result
CTRL-A	KEY_HOME
CTRL-B	KEY_LEFT
CTRL-E	KEY_END
CTRL-F	KEY_RIGHT
CTRL-N	tab
CTRL-P	KEY_BTAB
DEL	KEY_DC
backspace	KEY_BACKSPACE
carriage return	KEY_ENTER
newline	KEY_ENTER

All of the widgets use getchCDKObject internally for consistency.

EXAMPLE

To help demonstrate how to use the key bindings I will demonstrate a simple dialog box widget with help for each button. The following code segment creates a dialog box and a callback function named dialogHelpCB.

________________________________________

#include <cdk.h>
#ifdef HAVE_XCURSES
char *XCursesProgramName = "bind_ex";
#endif
static int dialogHelpCB(EObjectType cdktype GCC_UNUSED, void *object, void *clientData GCC_UNUSED, chtype key GCC_UNUSED)
{
    CDKDIALOG *dialog = (CDKDIALOG *)object;
    char *mesg[5];
    /* Check which button we are on. */
    if (dialog->currentButton == 0) {
        mesg[0] = "<C></U>Help for </U>Who<!U>.";
        mesg[1] = "<C>When this button is picked the name of the current";
        mesg[2] = "<C>user is displayed on the screen in a popup window.";
        popupLabel(ScreenOf(dialog), mesg, 3);
    } else if (dialog->currentButton == 1) {
        mesg[0] = "<C></U>Help for </U>Time<!U>.";
        mesg[1] = "<C>When this button is picked the current time is";
        mesg[2] = "<C>displayed on the screen in a popup window.";
        popupLabel(ScreenOf(dialog), mesg, 3);
    } else if (dialog->currentButton == 2) {
        mesg[0] = "<C></U>Help for </U>Date<!U>.";
        mesg[1] = "<C>When this button is picked the current date is";
        mesg[2] = "<C>displayed on the screen in a popup window.";
        popupLabel(ScreenOf(dialog), mesg, 3);
    } else if (dialog->currentButton == 3) {
        mesg[0] = "<C></U>Help for </U>Quit<!U>.";
        mesg[1] = "<C>When this button is picked the dialog box is exited.";
        popupLabel(ScreenOf(dialog), mesg, 2);
    }
    return (FALSE);
}
int main(void)
{
    /* Declare variables. */
    CDKSCREEN *cdkscreen;
    CDKDIALOG *question;
    WINDOW *cursesWin;
    char *buttons[40];
    char *message[40], *info[5], *loginName;
    char temp[256];
    int selection;
    time_t clck;
    struct tm *currentTime;
    /* Set up CDK. */
    cursesWin = initscr();
    cdkscreen = initCDKScreen(cursesWin);
    /* Start color. */
    initCDKColor();
    /* Set up the dialog box. */
    message[0] = "<C></U>Simple Command Interface";
    message[1] = "Pick the command you wish to run.";
    message[2] = "<C>Press </R>?<!R> for help.";
    buttons[0] = "Who";
    buttons[1] = "Time";
    buttons[2] = "Date";
    buttons[3] = "Quit";
    /* Create the dialog box. */
    question = newCDKDialog(cdkscreen, CENTER, CENTER,
                            message, 3, buttons, 4, A_REVERSE,
                            TRUE, TRUE, FALSE);
    /* Check if we got a null value back. */
    if (question == (CDKDIALOG *)0) {
        destroyCDKScreen(cdkscreen);
        /* End curses... */
        endCDK();
        /* Spit out a message. */
        printf("Oops. Can't seem to create the dialog box. Is the window too small?
");
        exit(1);
    }
    /* Create the key binding. */
    bindCDKObject(vDIALOG, question, '?', dialogHelpCB, 0);
    /* Activate the dialog box. */
    selection = 0;
    while (selection != 3) {
        /* Get the users button selection. */
        selection = activateCDKDialog(question, (chtype *)0);
        /* Check the results. */
        if (selection == 0) {
            /* Get the users login name. */
            info[0] = "<C>     </U>Login Name<!U>     ";
            loginName = getlogin();
            if (loginName == (char *)0) {
                strcpy(temp, "<C></R>Unknown");
            } else {
                sprintf(temp, "<C><%s>", loginName);
            }
            info[1] = copyChar(temp);
            popupLabel(ScreenOf(question), info, 2);
            freeChar(info[1]);
        } else if (selection == 1) {
            /* Print out the time. */
            time(&clck);
            currentTime = localtime(&clck);
            sprintf(temp, "<C>%d:%d:%d", currentTime->tm_hour,
                    currentTime->tm_min,
                    currentTime->tm_sec);
            info[0] = "<C>   </U>Current Time<!U>   ";
            info[1] = copyChar(temp);
            popupLabel(ScreenOf(question), info, 2);
            freeChar(info[1]);
        } else if (selection == 2) {
            /* Print out the date. */
            time(&clck);
            currentTime = localtime(&clck);
            sprintf(temp, "<C>%d/%d/%02d", currentTime->tm_mday,
                    currentTime->tm_mon,
                    currentTime->tm_year % 100);
            info[0] = "<C>   </U>Current Date<!U>   ";
            info[1] = copyChar(temp);
            popupLabel(ScreenOf(question), info, 2);
            freeChar(info[1]);
        }
    }
    /* Clean up. */
    destroyCDKDialog(question);
    destroyCDKScreen(cdkscreen);
    delwin(cursesWin);
    endCDK();
    exit(0);
}

SEE ALSO

cdk(3), cdk_display(3), cdk_screen(3)

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