Test Julia dlopen function

dll.c

#include <windows.h>
#include <direct.h>
#include <assert.h>
#include <stdio.h>
#define _OS_WINDOWS_

int isabspath(const char *in) {
#ifdef _OS_WINDOWS_
    char c0 = in[0];
    if (c0 == '/' || c0 == '\\') {
        return 1; // absolute path relative to %CD% (current drive), or UNC
    } else if (c0 && in[1] == ':') {
        char c2 = in[2];
        return c2 == '/' || c2 == '\\'; // absolute path with drive name
    }
#else
    if (in[0] == '/')
        return 1; // absolute path
#endif
    return 0; // relative path
}

#if defined(__APPLE__)
static char const *const extensions[] = {"", ".dylib"};
#elif defined(_OS_WINDOWS_)
static char const *const extensions[] = {"", ".dll"};
extern volatile int needsSymRefreshModuleList;
#else
static char const *const extensions[] = {"", ".so"};
#endif
#define N_EXTENSIONS (sizeof(extensions) / sizeof(char *))

static int endswith_extension(const char *path) {
    if (!path)
        return 0;
    size_t len = strlen(path);
    // Skip the first one since it is empty
    for (size_t i = 1; i < N_EXTENSIONS; i++) {
        const char *ext = extensions[i];
        size_t extlen = strlen(ext);
        if (len < extlen)
            return 0;
        // Skip version extensions if present
        size_t j = len - 1;
        while (j > 0) {
            if (path[j] == '.' || (path[j] >= '0' && path[j] <= '9'))
                j--;
            else
                break;
        }
        if ((j == len - 1 || path[j + 1] == '.') &&
            memcmp(ext, path + j - extlen + 1, extlen) == 0) {
            return 1;
        }
    }
    return 0;
}

#define PATHBUF 4096

#define JL_RTLD(flags, FLAG) (flags & JL_RTLD_##FLAG ? RTLD_##FLAG : 0)

#ifdef _OS_WINDOWS_
static void win32_formatmessage(DWORD code, char *reason, int len) {
    DWORD res;
    LPWSTR errmsg;
    res = FormatMessageW(
        FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM |
            FORMAT_MESSAGE_IGNORE_INSERTS | FORMAT_MESSAGE_MAX_WIDTH_MASK,
        NULL, code, MAKELANGID(LANG_ENGLISH, SUBLANG_ENGLISH_US),
        (LPWSTR)&errmsg, 0, NULL);
    if (!res && (GetLastError() == ERROR_MUI_FILE_NOT_FOUND ||
                 GetLastError() == ERROR_RESOURCE_TYPE_NOT_FOUND)) {
        res = FormatMessageW(
            FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM |
                FORMAT_MESSAGE_IGNORE_INSERTS | FORMAT_MESSAGE_MAX_WIDTH_MASK,
            NULL, code, 0, (LPWSTR)&errmsg, 0, NULL);
    }
    res = WideCharToMultiByte(CP_UTF8, 0, errmsg, -1, reason, len, NULL, NULL);
    assert(res > 0 || GetLastError() == ERROR_INSUFFICIENT_BUFFER);
    reason[len - 1] = '\0';
    LocalFree(errmsg);
}
#endif

void *jl_dlopen(const char *filename, unsigned flags) {
#if defined(_OS_WINDOWS_)
    size_t len = MultiByteToWideChar(CP_UTF8, 0, filename, -1, NULL, 0);
    if (!len)
        return NULL;
    WCHAR *wfilename = (WCHAR *)alloca(len * sizeof(WCHAR));
    if (!MultiByteToWideChar(CP_UTF8, 0, filename, -1, wfilename, len))
        return NULL;
    HANDLE lib = LoadLibraryExW(wfilename, NULL, LOAD_WITH_ALTERED_SEARCH_PATH);
    // if (lib)
    //    needsSymRefreshModuleList = 1;
    return lib;
#else
    dlerror(); /* Reset error status. */
    return dlopen(filename, (flags & JL_RTLD_NOW ? RTLD_NOW : RTLD_LAZY) |
                                JL_RTLD(flags, LOCAL) | JL_RTLD(flags, GLOBAL)
#ifdef RTLD_NODELETE
                                | JL_RTLD(flags, NODELETE)
#endif
#ifdef RTLD_NOLOAD
                                | JL_RTLD(flags, NOLOAD)
#endif
#if defined(RTLD_DEEPBIND) &&                                                  \
    !(defined(JL_ASAN_ENABLED) || defined(JL_TSAN_ENABLED) ||                  \
      defined(JL_MSAN_ENABLED))
                                | JL_RTLD(flags, DEEPBIND)
#endif
#ifdef RTLD_FIRST
                                | JL_RTLD(flags, FIRST)
#endif
    );
#endif
}

void *jl_load_dynamic_library(const char *modname, unsigned flags,
                              int throw_err) {
    char path[PATHBUF], relocated[PATHBUF];
    int i;
#ifdef _OS_WINDOWS_
    int err;
#endif
    void *handle;
    int abspath;
    // number of extensions to try — if modname already ends with the
    // standard extension, then we don't try adding additional extensions
    int n_extensions = endswith_extension(modname) ? 1 : N_EXTENSIONS;

    abspath = isabspath(modname);

    assert(abspath != 0);

    // now fall back and look in default library paths, for all extensions
    for (i = 0; i < n_extensions; i++) {
        const char *ext = extensions[i];
        path[0] = '\0';
        snprintf(path, PATHBUF, "%s%s", modname, ext);
        handle = jl_dlopen(path, flags);
        if (handle)
            goto done;
#ifdef _OS_WINDOWS_
        err = GetLastError();
        break; // LoadLibrary already tested the rest
#endif
    }

notfound:
    if (throw_err) {
#ifdef _OS_WINDOWS_
        char reason[256];
        win32_formatmessage(err, reason, sizeof(reason));
#else
        const char *reason = dlerror();
#endif
#ifndef __clang_analyzer__
        // Hide the error throwing from the analyser since there isn't a way to
        // express "safepoint only when throwing error" currently.
        printf("could not load library \"%s\"\n%s", modname, reason);
#endif
    }
    handle = NULL;

done:
    return handle;
}

int main(int argc, char const *argv[]) {

    // write your path of dll
    const char libname[] = "C:\\msys64\\home\\meta\\dist\\bin\\libcoinmumps-2.dll";

    int flags = 0;
    int throw_error = 1;

    void *handle = jl_load_dynamic_library(libname, flags, throw_error);

    if (handle) {
        printf("successful\n");
    }

done:
    return 0;
}

dll.jl

function dlopen(s::AbstractString, flags::Integer=0; throw_error::Bool=true)
    ret = ccall(:jl_load_dynamic_library, Ptr{Cvoid}, (Cstring, UInt32, Cint), s, flags, Cint(throw_error))
    if ret == C_NULL
        return nothing
    end
    return ret
end

libname = "C:\\msys64\\home\\meta\\dist\\bin\\libcoinmumps-2.dll"

dlopen(libname)