Hi guys,I still using PB 12.5 classic on a Windows 7 64bits machines,due to it doesn't has capablity to read xlsx file then I tried to build a dll which was calling the library to try to read xlsx file but they're  all occured exception which were 'Bad runtime function reference' and not working 

let me elaborate my scenario 

I tried to build dll file from libraries which are from github

#1 xlnt 

https://github.com/tfussell/xlnt

I tried to built  dlls with this library,one was built  with MSVC++ 2019 and another was built with MinGW  g++ 10.2.0  ,they both are not working ,I show you the code 

 readelmxlsx3.h file

________________________________________________________________________________________

extern "C"
{

__declspec(dllexport) int __stdcall readelmlist(const char* path, int& retrecordscount, char** prodno);
}

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  readelmxlsx3.cpp file

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#include "readelmxlsx3.h"
#include <xlnt/xlnt.hpp>
#include <algorithm>
#include <cctype>
#include <locale>
#include <codecvt>
#include <cstring>

using namespace std;

static inline void ltrim(std::string& s) {
s.erase(s.begin(), std::find_if(s.begin(), s.end(), [](int ch) {
return !std::isspace(ch);
}));
}

// trim from end (in place)
static inline void rtrim(std::string& s) {
s.erase(std::find_if(s.rbegin(), s.rend(), [](int ch) {
return !std::isspace(ch);
}).base(), s.end());
}

// trim from both ends (in place)
static inline void trim(std::string& s) {
ltrim(s);
rtrim(s);
}

// trim from start (copying)
static inline std::string ltrim_copy(std::string s) {
ltrim(s);
return s;
}

// trim from end (copying)
static inline std::string rtrim_copy(std::string s) {
rtrim(s);
return s;
}

// trim from both ends (copying)
static inline std::string trim_copy(std::string s) {
trim(s);
return s;
}

int __stdcall readelmlist(const char* path, int& retrecordscount, char** prodno)
{
xlnt::workbook wb;

wb.load(path);
auto ws = wb.sheet_by_index(0);



std::clog << "Processing spread sheet" << std::endl;
std::clog << "Creating a single vector which stores the whole spread sheet" << std::endl;
int rowcounts = 0;
std::vector<std::vector<std::string>> theWholeSpreadSheet;
int myrows = 0;
for (auto row : ws.rows(false))
{

if (myrows > 0)
{
int cols = 0;
for (auto cell : row)
{
std::clog << cell.to_string() << std::endl;
if (cols == 0)
{
std::string prodnostr = cell.to_string();
trim(prodnostr);
size_t prodnosize = prodnostr.length() + 1;
strcpy_s(prodno[myrows - 1], prodnosize, prodnostr.c_str());
}

cols++;
}
}
myrows++;
}
retrecordscount = myrows - 1;
return 0;
}

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#2 openXLSX

https://github.com/troldal/OpenXLSX

I tried to build a dll from this library as well with MSVC++ 2019 as well,it doesn't work as well 

 readelmxlsx3.h file

________________________________________________________________________________________ 

extern "C"
{

__declspec(dllexport) int __stdcall readelmlist(const char* path, int& retrecordscount, char** prodno);
}

________________________________________________________________________________________ 

readelmxlsx3.cpp file

________________________________________________________________________________________

#include <OpenXLSX.hpp>
#include <iostream>
#include <algorithm>
#include <cctype>
#include <locale>
#include <codecvt>
#include <string>
#include <wchar.h>

using namespace std;
using namespace OpenXLSX;

// generic solution
template <class T>
int numDigits(T number)
{
int digits = 0;
if (number < 0) digits = 1; // remove this line if '-' counts as a digit
while (number) {
number /= 10;
digits++;
}
return digits;
}

static inline void ltrim(std::string& s) {
s.erase(s.begin(), std::find_if(s.begin(), s.end(), [](int ch) {
return !std::isspace(ch);
}));
}

// trim from end (in place)
static inline void rtrim(std::string& s) {
s.erase(std::find_if(s.rbegin(), s.rend(), [](int ch) {
return !std::isspace(ch);
}).base(), s.end());
}

// trim from both ends (in place)
static inline void trim(std::string& s) {
ltrim(s);
rtrim(s);
}

// trim from start (copying)
static inline std::string ltrim_copy(std::string s) {
ltrim(s);
return s;
}

// trim from end (copying)
static inline std::string rtrim_copy(std::string s) {
rtrim(s);
return s;
}

// trim from both ends (copying)
static inline std::string trim_copy(std::string s) {
trim(s);
return s;
}

int __stdcall readelmlist(const char* path, int& retrecordscount, char ** prodno)
{

XLDocument doc;
doc.open(path);
auto wks = doc.workbook().worksheet("Sheet1");

auto rng = wks.range(XLCellReference("A2"), XLCellReference(50000, 1));

retrecordscount = 0;

for (auto& cell : rng)
{
if (cell.valueType() == XLValueType::Empty)
break;
else if (cell.valueType() == XLValueType::Integer)
{
if (numDigits(cell.value().get<int>()) == 8)
{
std::string numbervaluestr = std::to_string(cell.value().get<int>());
if (numbervaluestr.size() != 0)
{
size_t prodnosize = numbervaluestr.length() + 1;
strcpy_s(prodno[retrecordscount], prodnosize, numbervaluestr.c_str());
retrecordscount++;
}
}
}
else if (cell.valueType() == XLValueType::String)
{
std::string numbervaluestr = cell.value().get<std::string>();
trim(numbervaluestr);
size_t prodnosize = numbervaluestr.length() + 1;
strcpy_s(prodno[retrecordscount], prodnosize, numbervaluestr.c_str());
retrecordscount++;
}
}

return 0;
}

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finally my PB implementation

declared the function in Global external functions section

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function long readelmlist(string path,ref long retrecordscount,ref string  prodno[]) LIBRARY "readelmxlsx2.dll"  Alias for 'readelmlist;Ansi'

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then I tried to call this function

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string ls_path,ls_name

string ls_prodno[]

long ll_retrecordscount,ll_result
long li_i
string ls_prodnocurr,ls_prodnobefore

li_i=getfileopenname("open file",ls_path,ls_name,"txt xlsx", "Text Files (*.txt),*.txt,Excel 2007 Files (*.xlsx),*.xlsx" )

if li_i>0 then
for ll_retrecordscount=1 to 50000
 ls_prodno[ll_retrecordscount]=space(20)
next
ls_prodno=space(50000)
ll_retrecordscount=0

ll_result=readelmlistest(ls_path,ll_retrecordscount,ls_prodno)
if ll_result<>0 then
uf_ok("read xlsx file error")
return
end if
end if

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they're so bizarre even I checked the dlls files on dependency walker,their function names were normal which are NOT mangling and didn't missing any dependencies which are some dlls

I ever thought if there some errors in the code and I tried to debug the dll on VC++,it's so bizaree that everything worked perfectly well when I was debugging

what wrong I have done? thank you so much