Usage of an external library (bcm2835) with halcompile

//   This is a component for EMC2 HAL
//   Copyright 2006 John Kasunich <jmkasunich at sourceforge dot net>
//
//   This program is free software; you can redistribute it and/or
//   modify it under the terms of version 2 of the GNU General
//   Public License as published by the Free Software Foundation.
//
//   This program is distributed in the hope that it will be useful,
//   but WITHOUT ANY WARRANTY; without even the implied warranty of
//   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//   GNU General Public License for more details.
//
//   You should have received a copy of the GNU General Public License
//   along with this program; if not, write to the Free Software
//   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
component abs "Compute the absolute value and sign of the input signal";

pin in float in "Analog input value" ;
pin out float out "Analog output value, always positive";
pin out bit sign "Sign of input, false for positive, true for negative" ;
pin out bit is_positive "TRUE if input is positive, FALSE if input is 0 or negative";
pin out bit is_negative "TRUE if input is negative, FALSE if input is 0 or positive";

function _;
license "GPL";
;;
FUNCTION(_) {
    double tmp = in;
    if ( tmp >= 0.0 ) {
	sign = 0;
	out = tmp;
    } else {
	sign = 1;
	out = -tmp;
    }

    if (tmp > 0.000001) is_positive = 1;
    else is_positive = 0;

    if (tmp < -0.000001) is_negative = 1;
    else is_negative = 0;
}

/* Autogenerated by /usr/bin/halcompile on Sat Jul 27 00:13:37 2019 -- do not edit */
#include "rtapi.h"
#ifdef RTAPI
#include "rtapi_app.h"
#endif
#include "rtapi_string.h"
#include "rtapi_errno.h"
#include "hal.h"
#include "rtapi_math64.h"

static int comp_id;

#ifdef MODULE_INFO
MODULE_INFO(linuxcnc, "component:abs:Compute the absolute value and sign of the input signal");
MODULE_INFO(linuxcnc, "pin:in:float:0:in:Analog input value:None:None");
MODULE_INFO(linuxcnc, "pin:out:float:0:out:Analog output value, always positive:None:None");
MODULE_INFO(linuxcnc, "pin:sign:bit:0:out:Sign of input, false for positive, true for negative:None:None");
MODULE_INFO(linuxcnc, "pin:is_positive:bit:0:out:TRUE if input is positive, FALSE if input is 0 or negative:None:None");
MODULE_INFO(linuxcnc, "pin:is_negative:bit:0:out:TRUE if input is negative, FALSE if input is 0 or positive:None:None");
MODULE_INFO(linuxcnc, "funct:_:1:");
MODULE_INFO(linuxcnc, "license:GPL");
MODULE_LICENSE("GPL");
#endif // MODULE_INFO


struct __comp_state {
    struct __comp_state *_next;
    hal_float_t *in;
    hal_float_t *out;
    hal_bit_t *sign;
    hal_bit_t *is_positive;
    hal_bit_t *is_negative;
};
struct __comp_state *__comp_first_inst=0, *__comp_last_inst=0;

static void _(struct __comp_state *__comp_inst, long period);
static int __comp_get_data_size(void);
#undef TRUE
#define TRUE (1)
#undef FALSE
#define FALSE (0)
#undef true
#define true (1)
#undef false
#define false (0)

static int export(char *prefix, long extra_arg) {
    char buf[HAL_NAME_LEN + 1];
    int r = 0;
    int sz = sizeof(struct __comp_state) + __comp_get_data_size();
    struct __comp_state *inst = hal_malloc(sz);
    memset(inst, 0, sz);
    r = hal_pin_float_newf(HAL_IN, &(inst->in), comp_id,
        "%s.in", prefix);
    if(r != 0) return r;
    r = hal_pin_float_newf(HAL_OUT, &(inst->out), comp_id,
        "%s.out", prefix);
    if(r != 0) return r;
    r = hal_pin_bit_newf(HAL_OUT, &(inst->sign), comp_id,
        "%s.sign", prefix);
    if(r != 0) return r;
    r = hal_pin_bit_newf(HAL_OUT, &(inst->is_positive), comp_id,
        "%s.is-positive", prefix);
    if(r != 0) return r;
    r = hal_pin_bit_newf(HAL_OUT, &(inst->is_negative), comp_id,
        "%s.is-negative", prefix);
    if(r != 0) return r;
    rtapi_snprintf(buf, sizeof(buf), "%s", prefix);
    r = hal_export_funct(buf, (void(*)(void *inst, long))_, inst, 1, 0, comp_id);
    if(r != 0) return r;
    if(__comp_last_inst) __comp_last_inst->_next = inst;
    __comp_last_inst = inst;
    if(!__comp_first_inst) __comp_first_inst = inst;
    return 0;
}
static int default_count=1, count=0;
char *names[16] = {0,};
RTAPI_MP_INT(count, "number of abs");
RTAPI_MP_ARRAY_STRING(names, 16, "names of abs");
int rtapi_app_main(void) {
    int r = 0;
    int i;
    comp_id = hal_init("abs");
    if(comp_id < 0) return comp_id;
    if(count && names[0]) {
        rtapi_print_msg(RTAPI_MSG_ERR,"count= and names= are mutually exclusive\n");
        return -EINVAL;
    }
    if(!count && !names[0]) count = default_count;
    if(count) {
        for(i=0; i<count; i++) {
            char buf[HAL_NAME_LEN + 1];
            rtapi_snprintf(buf, sizeof(buf), "abs.%d", i);
            r = export(buf, i);
            if(r != 0) break;
       }
    } else {
        int max_names = sizeof(names)/sizeof(names[0]);
        for(i=0; (i < max_names) && names[i]; i++) {
            if (strlen(names[i]) < 1) {
                rtapi_print_msg(RTAPI_MSG_ERR, "names[%d] is invalid (empty string)\n", i);
                r = -EINVAL;
                break;
            }
            r = export(names[i], i);
            if(r != 0) break;
       }
    }
    if(r) {
        hal_exit(comp_id);
    } else {
        hal_ready(comp_id);
    }
    return r;
}

void rtapi_app_exit(void) {
    hal_exit(comp_id);
}

#undef FUNCTION
#define FUNCTION(name) static void name(struct __comp_state *__comp_inst, long period)
#undef EXTRA_SETUP
#define EXTRA_SETUP() static int extra_setup(struct __comp_state *__comp_inst, char *prefix, long extra_arg)
#undef EXTRA_CLEANUP
#define EXTRA_CLEANUP() static void extra_cleanup(void)
#undef fperiod
#define fperiod (period * 1e-9)
#undef in
#define in (0+*__comp_inst->in)
#undef out
#define out (*__comp_inst->out)
#undef sign
#define sign (*__comp_inst->sign)
#undef is_positive
#define is_positive (*__comp_inst->is_positive)
#undef is_negative
#define is_negative (*__comp_inst->is_negative)


#line 27 "abs.comp"
FUNCTION(_) {
    double tmp = in;
    if ( tmp >= 0.0 ) {
	sign = 0;
	out = tmp;
    } else {
	sign = 1;
	out = -tmp;
    }

    if (tmp > 0.000001) is_positive = 1;
    else is_positive = 0;

    if (tmp < -0.000001) is_negative = 1;
    else is_negative = 0;
}

static int __comp_get_data_size(void) { return 0; }