[SOLVED]: Can't find 'boot_...' symbol when trying to use an installed XS module

[stevieb]

update: Solved in Re: Can't find 'boot_...' symbol when trying to use an installed XS module. /update

I'm working on my next Raspberry Pi project, and am having an issue using the XS module. I generated the XS using Inline::C, copied the file into the distribution directory, and compiled it successfully. However, I'm getting:

Can't find 'boot_RPi__ADC__MCP3008' symbol in /usr/local/lib/perl/5.18
+.2/auto/RPi/ADC/MCP3008/MCP3008.so
 at /usr/local/lib/perl/5.18.2/RPi/ADC/MCP3008.pm line 12.

I've gone through an hour's worth of search results, but none explain how I should fix this so I'm at a bit of a loss. All I know is that the error is being generated by XSLoader.

Can the XS Monks have a look to see what I may be missing? I'll happily provide more information/code/files if necessary.

My XS code:

#include "EXTERN.h"
#include "perl.h"
#include "XSUB.h"

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <stdint.h>
#include <string.h>
#include <errno.h>

#include <wiringPi.h>
#include <wiringPiSPI.h>

static int fd;

void load_spi_driver (){
    if (system("gpio load spi") == -1){
        fprintf (stderr, "Can't load the SPI driver: %s\n", strerror (
+errno)) ;
        exit (EXIT_FAILURE) ;
    }
}

void spi_setup (int spi_channel){
    if ((fd = wiringPiSPISetup(spi_channel, 1000000)) < 0){
        fprintf (stderr, "Can't open the SPI bus: %s\n", strerror (err
+no)) ;
        exit (EXIT_FAILURE) ;
    }
}

int fetch (int load_spi, int spi, int mode, int input){

    if(load_spi == TRUE){
        loadSpiDriver();
    }

    wiringPiSetup () ;
    spiSetup(spi);

    if(mode == 1){
        // single-ended requires 0x08
        mode = mode << 3;
    }

    if(input < 0 || input > 7){
        return -1;
    }

    // start bit

    unsigned char buffer[3] = {1};

    buffer[1] = (mode + input) << 4;

    wiringPiSPIDataRW(spi, buffer, 3);

    // get the last 10 bits

    return ((buffer[1] & 3) << 8) + buffer[2];
}

MODULE = MCP3008  PACKAGE = MCP3008

PROTOTYPES: DISABLE

void
load_spi_driver ()
        PREINIT:
        I32* temp;
        PPCODE:
        temp = PL_markstack_ptr++;
        load_spi_driver();
        if (PL_markstack_ptr != temp) {
          /* truly void, because dXSARGS not invoked */
          PL_markstack_ptr = temp;
          XSRETURN_EMPTY; /* return empty stack */
        }
        /* must have used dXSARGS; list context implied */
        return; /* assume stack size is correct */

void
spi_setup (spi_channel)
    int    spi_channel
        PREINIT:
        I32* temp;
        PPCODE:
        temp = PL_markstack_ptr++;
        spi_setup(spi_channel);
        if (PL_markstack_ptr != temp) {
          /* truly void, because dXSARGS not invoked */
          PL_markstack_ptr = temp;
          XSRETURN_EMPTY; /* return empty stack */
        }
        /* must have used dXSARGS; list context implied */
        return; /* assume stack size is correct */

int
fetch (load_spi, spi, mode, input)
    int    load_spi
    int    spi
    int    mode
    int    input

The relevant piece in the module:

require XSLoader;
XSLoader::load('RPi::ADC::MCP3008', $VERSION);

...and just in case, my makefile:

use strict;
use warnings FATAL => 'all';
use ExtUtils::MakeMaker;

WriteMakefile(
    NAME             => 'RPi::ADC::MCP3008',
    AUTHOR           => q{Steve Bertrand <[e-mail]>},
    VERSION_FROM     => 'lib/RPi/ADC/MCP3008.pm',
    ABSTRACT_FROM    => 'lib/RPi/ADC/MCP3008.pm',
    LICENSE          => 'Perl_5',
    PL_FILES         => {},
    LIBS             => ['-lwiringPi', '-lpthread'],
    MIN_PERL_VERSION => 5.006,
    CONFIGURE_REQUIRES => {
        'ExtUtils::MakeMaker' => 0,
    },
    BUILD_REQUIRES => {
        'Test::More' => 0,
    },
    PREREQ_PM => {
    },
    dist  => { COMPRESS => 'gzip -9f', SUFFIX => 'gz', },
    clean => { FILES => 'RPi-ADC-MCP3008-*' },
);

[stevieb]

Rubber duck debugging to the rescue once again...

In my XS file, I had this:

MODULE = MCP3008  PACKAGE = MCP3008

Whereby these two directives require the full package/module name:

MODULE = RPi::ADC::MCP3008  PACKAGE = RPi::ADC::MCP3008

After that change, all is well in the world again.