Has anyone tried compiling FindLib with the visual studio 2012 or later.

This is ok with visual studio 2008 and an old version of ocaml 3.11.
I have also tried the most recent release tar balls of ocaml and flex without any success.

FindLib package has a prebuild configuration to test loading dlls as:

ocaml unix.cma  - > fails with Reason: .\dllunix.dll: Invalid access to memory location.

(This command line routine has a dependency of ocamlrun.exe, pervasive.cma and dllunix.dll
which I have compiled all from src code using vs 2012. I have tried both static and dynamic linkage to no avail.)

This error originates from  flexdll.c in the FlexDLL package. It tries to call LoadLibraryEx and is returning null.

Further Testing

// A test to load dllunix dynamically ....
#include <flexdll.h>
#include <stdio.h>
#include <windows.h>

int main(int argc, char *argv[]) {
    void *handle;
    printf("Try open: %s\n", argv[1]);
    handle = flexdll_dlopen(argv[1], FLEXDLL_RTLD_GLOBAL);
    printf("Handle: %p\n", handle);
    if (handle == NULL) {
            printf("Error code: %d\n", GetLastError());
            printf("Error message: %s\n", flexdll_dlerror());
    }
    return 0;
}

cl -nologo -MD -I"D:\external\OCaml\FlexDLL_034" -c Testdll.c
flexlink -v -merge-manifest -exe -o testdll Testdll.obj

Direct test of dllunix.dll

$./testdll dllunix.dll

Try open:dllunix.dll
Error code: 998
Error message: Invalid access to memory location.

Instead of using dllunix.dll I have tried to compile a simple program for testing

A simplified test

#include <stdio.h>
int x = 10;
void dump_x(void) {
printf("myplugin finds the value : \nx=%i\n", x); fflush( stdout );
}

cl -nologo -MD  -I.. -c myplug.c
flexlink.exe -chain msvc -merge-manifest  -v -o myplug.dll  myplug.obj -link ws2_32.lib

$./testdll  myplug.dll

Try open: myplug.dll
Error code: 998
Error message: Invalid access to memory location.

Note that   the dump exe in flexdll fails in the same manner

In vs2008 build this is ok


$./testdll  myplug.dll

Try open: myplug.dll
Handle: 01F6DB78

Even running the test/dump.exe from flexDLL is ok

$ ./dump myplug.dll

INIT
Dynamic symbol at 00412000 (size = 12)
[0]  00402227: __iob_func
[1]  00401BA0: api
[2]  00402E7C: fflush
[3]  004017F0: flexdll_dlclose
[4]  004018B0: flexdll_dlerror
[5]  00401580: flexdll_dlopen
[6]  00401860: flexdll_dlsym
[7]  00401900: flexdll_dump_exports
[8]  00401A60: flexdll_dump_relocations
[9]  00401000: flexdll_relocate
[10]  00401BC0: main
[11]  00401D0E: printf
OK
** Loading myplug.dll
** handle = 01FEDB78
Dynamic symbol at 004C0000 (size = 4)
[0]  004B1000: FlexDLLiniter@12
[1]  004B1170: dump_x
[2]  004B11A0: torun
[3]  004BC014: x
myplugin finds the value :
x=10




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