source: bootcd/isolinux/syslinux-6.03/gpxe/src/include/console.h

#ifndef CONSOLE_H
#define CONSOLE_H

#include <gpxe/tables.h>

/** @file
 *
 * User interaction.
 *
 * Various console devices can be selected via the build options
 * CONSOLE_FIRMWARE, CONSOLE_SERIAL etc.  The console functions
 * putchar(), getchar() and iskey() delegate to the individual console
 * drivers.
 *
 */

FILE_LICENCE ( GPL2_OR_LATER );

/**
 * A console driver
 *
 * Defines the functions that implement a particular console type.
 * Must be made part of the console drivers table by using
 * #__console_driver.
 *
 * @note Consoles that cannot be used before their initialisation
 * function has completed should set #disabled=1 initially.  This
 * allows other console devices to still be used to print out early
 * debugging messages.
 *
 */
struct console_driver {
        /** Console is disabled.
         *
         * The console's putchar(), putline(), getchar() and iskey()
         * methods will not be called while #disabled==1. Typically
         * the console's initialisation functions will set #disabled=0
         * upon completion.
         *
         */
        int disabled;

        /** Write a character to the console.
         *
         * @v character         Character to be written
         * @ret None            -
         * @err None            -
         *
         */
        void ( *putchar ) ( int character );

        /** Write an entire line to the console.
         * This is intended to be used by line-oriented output media,
         * like system logging facilities or line printers.
         * Line output will not contain non-printable characters.
         *
         * @v linebuffer        Pointer to the \0-terminated line
         * @ret None            -
         * @err None            -
         */
        void ( * putline ) ( unsigned char * linebuffer );

        /** Read a character from the console.
         *
         * @v None              -
         * @ret character       Character read
         * @err None            -
         *
         * If no character is available to be read, this method will
         * block.  The character read should not be echoed back to the
         * console.
         *
         */
        int ( *getchar ) ( void );

        /** Check for available input.
         *
         * @v None              -
         * @ret True            Input is available
         * @ret False           Input is not available
         * @err None            -
         *
         * This should return True if a subsequent call to getchar()
         * will not block.
         *
         */
        int ( *iskey ) ( void );
};

/** Console driver table */
#define CONSOLES __table ( struct console_driver, "consoles" )

/**
 * Mark a <tt> struct console_driver </tt> as being part of the
 * console drivers table.
 *
 * Use as e.g.
 *
 * @code
 *
 *   struct console_driver my_console __console_driver = {
 *      .putchar = my_putchar,
 *      .getchar = my_getchar,
 *      .iskey = my_iskey,
 *   };
 *
 * @endcode
 *
 */
#define __console_driver __table_entry ( CONSOLES, 01 )

/* Function prototypes */

extern void putchar ( int character );
extern int getchar ( void );
extern int iskey ( void );
extern int getkey ( void );

#endif /* CONSOLE_H */