Perl Win32::API – dependent DLL not detected - c

Question

This perl script is modified from the #ikegami parallel arrays version to include test data.
On execution, it fails with this error message:
“The program can’t start because gsl.dll is missing from your computer. Try reinstalling the program to fix the problem.”
However, when a C program runs PolyFit it executes without error. The source code for it follows the perl script below.
gsl.dll is present in the same directory as PolyFitGSL.dll, D:/prjct/model/code/SRS1/binaries/:
# #ikegami parallel arrays version
use 5.014;
use strict;
use warnings;
use feature qw( state );
use Config qw( %Config );
use Win32::API qw( );
use constant PTR_SIZE => $Config{ptrsize};
use constant PTR_PACK_FORMAT =>
PTR_SIZE == 8 ? 'Q'
: PTR_SIZE == 4 ? 'L'
: die("Unrecognized ptrsize\n");
use constant PTR_WIN32API_TYPE =>
PTR_SIZE == 8 ? 'DWORD64'
: PTR_SIZE == 4 ? 'DWORD32'
: die("Unrecognized ptrsize\n");
# local definitions
my $fitorder = 3;
my #XVals = (1,2,3,4,5,6,7,8,9,10);
my #YVals = (12.36,12.32,12.31,12.37,12.44,12.44,12.5,12.46,12.48,12.51);
Win32::API::Type->typedef('uintptr_t' => PTR_WIN32API_TYPE);
my $dll = 'D:/prjct/model/code/SRS1/binaries/PolyFitGSL';
sub get_buffer_addr { unpack(PTR_PACK_FORMAT, pack('P', $_[0])) }
sub poly_fit {
my ($xvals, $yvals, $fitorder) = #_;
#$xvals == #$yvals
or croak("Mismatch in the number of X vals and Y vals");
state $PolyFit;
if (!$PolyFit) {
my $adjusted_proto = '
int __declspec PolyFit(
int numPts,
uintptr_t xVals,
uintptr_t yVals,
int fitOrder,
uintptr_t coef,
uintptr_t fitVals,
uintptr_t rSquared
)
';
$PolyFit = Win32::API::More->new($dll, $adjusted_proto)
or die("Can't link to PolyFit: $^E\n");
}
my $n = #$xvals;
my $xVals = pack("d$n", #$xvals);
my $yVals = pack("d$n", #$yvals);
my $coef = pack('d'.( $fitorder + 1 ), ( 0 )x( $fitorder + 1 ));
my $fit_vals = pack("d$n", ( 0 )x( $n ));
my $r_squared = pack('d', 0);
my $rv = $PolyFit->Call(
$n,
get_buffer_addr($xvals),
get_buffer_addr($yvals),
$fitorder,
get_buffer_addr($coef),
get_buffer_addr($fit_vals),
get_buffer_addr($r_squared),
);
# I'm assuming the return value indicates whether the call was successful or not?
return if !$rv;
}
my ($coef, $fitVals, $r_squared) = poly_fit(
\#XVals,
\#YVals,
$fitorder,
)
or die("Error");
When provided with an input data file, this C program runs successfully, with no error executing PolyFit
lang-C
// PolyFitFileData.cpp : This file contains the 'main' function. Program execution begins and ends there.
//
#include <stdlib.h>
#include "..\PolyFitGSL\PolyFitGSL.h"
#include <time.h>
#include <math.h>
#include <stdio.h>
#include <string.h>
int ReadSingleColDataFile(const char* filename, int numPts, int numHeaderRows, double* data)
{
int i;
double curNum;
char line[32];
FILE* fPtr;
fopen_s(&fPtr, filename, "r");
if (fPtr == NULL)
{
return 1;
}
for (i = 0; i < (numPts + numHeaderRows); i++)
{
if (fgets(line, 32, fPtr) != NULL)
{
if (i >= numHeaderRows)
{
curNum = strtod(line, NULL);
data[i - numHeaderRows] = curNum;
}
}
}
return 0;
}
int main(int argc, char** argv)
{
int i, n, resFit, lineNum;
double* xVals;
double* yVals;
double* coef;
double* estYVals;
double* rSquared;
FILE* fptr;
int fitOrder=1;
if (argc != 5)
{
printf_s("Pass in 4 args: \n(1) number of points \n(2) filename with data (Y values only, one per line, one header line)\n(3) Fit order\n(4) Output Filename (or empty string for none)");
exit(-1);
}
if (fopen_s(&fptr, argv[2], "r") != 0) {
printf("Error! opening input file");
// Program exits if file pointer returns NULL.
exit(-16);
}
n = atoi(argv[1]);
fitOrder = atoi(argv[3]);
xVals = (double*)malloc(n * sizeof(double));
yVals = (double*)malloc(n * sizeof(double));
if (fptr != NULL) {
char line[100];
lineNum = 0;
while ((fgets(line, sizeof line, fptr) != NULL) && lineNum < (n + 1)) /* read a line from a file */ {
if (lineNum > 0)
{
//then parse string and add double to list
yVals[lineNum - 1] = atof(line);
xVals[lineNum - 1] = (double)lineNum;
}
lineNum++;
}
fclose(fptr);
}
else {
return -22;
}
coef = (double*)malloc((fitOrder + 1) * sizeof(double));
estYVals = (double*)malloc(n * sizeof(double));
rSquared = (double*)malloc(sizeof(double));
resFit = PolyFit(n, xVals, yVals, fitOrder, coef, estYVals, rSquared);
//I can print out results to file now here, or to screen....
printf_s("Completed fit. Result from PolyFit function was %d.\n", resFit);
printf_s("Fit order: %d\n", fitOrder);
printf_s("RSquared: %f\n", *rSquared);
printf_s("Coefficients:\n");
for (i = 0; i < fitOrder + 1; i++)
{
printf_s("[x%d] %f\n", i, coef[i]);
}
printf_s("%d Data points (x,y,yFit):\n", n);
for (i = 0; i < n; i++)
{
printf_s("%f\t%f\t%f\n", xVals[i], yVals[i], estYVals[i]);
}
//if you pass in empty string "" then assume that you don't want to write to disk
fptr = NULL;
if (strlen(argv[4]) > 2)
{
if (fopen_s(&fptr, argv[4], "w") != 0) {
printf("Error! opening file for output");
// Program exits if file pointer returns NULL.
exit(-16);
}
fprintf_s(fptr,"Fit order: %d\n", fitOrder);
fprintf_s(fptr, "RSquared: %f\n", *rSquared);
fprintf_s(fptr, "Coefficients:\n");
for (i = 0; i < fitOrder + 1; i++)
{
fprintf_s(fptr, "[x%d] %f\n", i, coef[i]);
}
fprintf_s(fptr, "%d Data points (x,y,yFit):\n", n);
for (i = 0; i < n; i++)
{
fprintf_s(fptr, "%f\t%f\t%f\n", xVals[i], yVals[i], estYVals[i]);
}
fclose(fptr);
}
free(coef);
free(estYVals);
free(rSquared);
free(xVals);
free(yVals);
return 0;
}

Answer 1

This isn't a Perl problem per say; this is about letting Windows know where to find your DLLs. See Dynamic-Link Library Search Order.
The directory in which the script and thus the DLL reside can be obtained using
use FindBin qw( $RealBin );
Among other solution, you'll find switching the current directory to that directory
chdir($RealBin);
and adding it to the PATH
$ENV{PATH} = "$RealBin;$ENV{PATH}";