#include <stdio.h>
#include <sys/mman.h>
#include <fcntl.h>
#include <errno.h>
#include <unistd.h>
#include <string.h>


#if defined(BEAGLEBONE_BLACK) || 1

#include "pru/prussdrv.h"
#include "pru/pruss_intc_mapping.h"

#define PRU_NUM 	 	0
#define OFFSET_SHAREDRAM 	2048
#define PRUSS0_SHARED_DATARAM	4

static void *sharedMem;
static uint32_t *sharedMem_int;
static uint32_t pruEnabled = 0;

uint32_t BESPRUSetup(void)
{
    unsigned int ret;
    tpruss_intc_initdata pruss_intc_initdata = PRUSS_INTC_INITDATA;

    if (pruEnabled) return 0;
fprintf(stderr, "BESPRUSetup: About to init the PRUSS\n");
    /* Initialize the PRU */
    prussdrv_init ();

    /* Open PRU Interrupt */
    ret = prussdrv_open(PRU_EVTOUT_0);
    if (ret)
    {
        fprintf(stderr, "prussdrv_open open failed\n");
        return(pruEnabled);
    }

    /* Get the interrupt initialized */
    prussdrv_pruintc_init(&pruss_intc_initdata);

    /* Execute gamepad firmware on PRU */
    fprintf(stderr, "\tINFO: Executing example.\r\n");
    prussdrv_exec_program (PRU_NUM, "./gamepad.bin");

    /* Allocate Shared PRU memory. */
    //prussdrv_map_prumem(PRUSS0_SHARED_DATARAM, &sharedMem);
    //sharedMem_int = (uint32_t *) sharedMem;

    /* Done! */
    pruEnabled = 1;
fprintf(stderr, "PRU enabled!\n");
    return pruEnabled;
}

uint32_t BESPRUCheckState(void)
{
    if (!pruEnabled) return 0x0; //FFFFFFFF;

    /* Allocate Shared PRU memory. */
    prussdrv_map_prumem(PRUSS0_SHARED_DATARAM, &sharedMem);
    sharedMem_int = (uint32_t *) sharedMem;

    return(sharedMem_int[OFFSET_SHAREDRAM]);
}

void BESPRUShutdown(void)
{
    if (pruEnabled)
    {
        /* Disable PRU and close memory mapping*/
        prussdrv_pru_disable(PRU_NUM);
        prussdrv_exit ();
        pruEnabled = 0;
    }
}

#else /* defined(BEAGLEBONE_BLACK) */

uint32_t BESPRUSetup(void) { return(0); }
uint32_t BESPRUCheckState(void) { return(0xFFFFFFFF); }
void BESPRUShutdown(void) {}

#endif /* defined(BEAGLEBONE_BLACK) */


error message

debian@beaglebone:~/bes/src$ sudo arm-linux-gnueabihf-g++ pru.cpp -o prudd
/usr/lib/gcc/arm-linux-gnueabihf/6/../../../arm-linux-gnueabihf/Scrt1.o: In function `_start':
(.text+0x44): undefined reference to `main'
/tmp/ccgsFOfq.o: In function `BESPRUSetup()':
pru.cpp:(.text+0x114): undefined reference to `prussdrv_init'
pru.cpp:(.text+0x11a): undefined reference to `prussdrv_open'
pru.cpp:(.text+0x14a): undefined reference to `prussdrv_pruintc_init'
pru.cpp:(.text+0x168): undefined reference to `prussdrv_exec_program'
/tmp/ccgsFOfq.o: In function `BESPRUCheckState()':
pru.cpp:(.text+0x1de): undefined reference to `prussdrv_map_prumem'
/tmp/ccgsFOfq.o: In function `BESPRUShutdown()':
pru.cpp:(.text+0x224): undefined reference to `prussdrv_pru_disable'
pru.cpp:(.text+0x228): undefined reference to `prussdrv_exit'
collect2: error: ld returned 1 exit status