windows10 cannot load library

[Smawexi]

There is a corresponding DLL file in the directory, but the corresponding file cannot be found

import cffi
ffi = cffi.FFI()
lib = ffi.dlopen("D:/Work/produce/HuiHua25/tests/libapi.dll")

---

Execution error, output:

Traceback (most recent call last):
  File "D:\Work\produce\HuiHua25\tests\test.py", line 38, in <module>
    lib = ffi.dlopen("D:/Work/produce/HuiHua25/tests/libapi.dll")
  File "D:\fsy\Anaconda3\lib\site-packages\cffi\api.py", line 150, in dlopen
    lib, function_cache = _make_ffi_library(self, name, flags)
  File "D:\fsy\Anaconda3\lib\site-packages\cffi\api.py", line 834, in _make_ffi_library
    backendlib = _load_backend_lib(backend, libname, flags)
  File "D:\fsy\Anaconda3\lib\site-packages\cffi\api.py", line 830, in _load_backend_lib
    return backend.load_library(path, flags)
OSError: cannot load library 'D:/Work/produce/HuiHua25/tests/libapi.dll': error 0x7e

---

D:\Work\produce\HuiHua25\tests>dir
 驱动器 D 中的卷是 Data
 卷的序列号是 7E57-7B60

 D:\Work\produce\HuiHua25\tests 的目录

2025/01/13  00:46    <DIR>          .
2025/01/13  00:46    <DIR>          ..
2025/01/13  00:00    <DIR>          build
2025/01/13  00:00           326,301 key.c
2025/01/13  00:00            52,224 key.cp39-win_amd64.pyd
2025/01/13  00:29             4,017 key.pyx
2025/01/12  20:56         7,833,177 libapi.dll

[arigo]

Can you check if #64 helps?

[Smawexi]

Can you check if #64 helps?

Found a temporary solution, this can load normally.
Without adding the winmode=0 parameter, an error will occur

import ctypes
ctypes.CDLL("D:/Work/produce/HuiHua25/tests/libapi.dll", winmode=0)

[Smawexi]

I don't know how to solve it on CFFi

[arigo]

Are you running the latest version of CFFI?

[Smawexi]

Are you running the latest version of CFFI?

CFFI version: 1.17.1

[arigo]

I don't understand how the ctypes winmode=0 can help fix the problem. When called with a full path, the default value of winmode should be nt._LOAD_LIBRARY_SEARCH_DEFAULT_DIRS | nt._LOAD_LIBRARY_SEARCH_DLL_LOAD_DIR. If you specify 0 explicitly, then these two flags are not present and Windows does not search for dependent DLLs elsewhere. How doing that makes it work is beyond me.

I'd recommend to try to understand why you get this Windows error 0x7e in ctypes or not depending on the flags you pass in ctypes' winmode argument.

In recent versions of CFFI you can also pass flags by calling ffi.dlopen("some/path", flags), but the value flags=0 is the default here and it will be replaced with real flags like in the winmode=None case of ctypes. Try with another value of flags, e.g. 16.