>>> import plyvel
>>> db = plyvel.DB('e:/temp/testdb/', create_if_missing=True)
>>> os.listdir("e:/temp/testdb/")
['000003.log', 'CURRENT', 'LOCK', 'LOG', 'MANIFEST-000002']
```
---
### Author:  [@Reload](https://discourse.cmake.org/u/Reload)
#### Post date: [November 21, 2023, 11:08am UTC](https://discourse.cmake.org/t/help-with-linking-snappy-to-leveldb-windows-pay-40/9472/7 "2023-11-21T11:08:44Z")
That’s weird… It didn’t work for me
---
### Author:  [@retif](https://discourse.cmake.org/u/retif)
#### Post date: [November 21, 2023, 11:33am UTC](https://discourse.cmake.org/t/help-with-linking-snappy-to-leveldb-windows-pay-40/9472/8 "2023-11-21T11:33:39Z")
Can’t see on your screenshot if libraries are in fact inside the path you are adding. But if it’s the same path, then it is weird indeed. Is the error absolutely the same as before?
Also, looking at your DLLs sizes, mine are different:
```auto
$ du -hs ./*.dll
260K ./leveldb.dll
212K ./snappy.dll
```
I’ve built Release configuration for both, and it was the latest commits from both their repositories. If you have used the same revisions and configuration, then it is strange that your `leveldb.dll` is more than 3 times bigger than mine.
I would also check that `leveldb` build actually did link to `snappy`, because it doesn’t fail it it is not found, just builds without it.
---
### Author:  [@Reload](https://discourse.cmake.org/u/Reload)
#### Post date: [November 21, 2023, 11:42am UTC](https://discourse.cmake.org/t/help-with-linking-snappy-to-leveldb-windows-pay-40/9472/9 "2023-11-21T11:42:47Z")
Yes, the error is exactly the same. I’m building leveldb 1.22 and snappy 1.1.9
As specified here - [https://github.com/wbolster/plyvel/tree/main/scripts](https://github.com/wbolster/plyvel/tree/main/scripts)
Have you built with the same cmake parameters and under windows? Why don’t we go to telegram? It’ll be quicker and more convenient
---
### Author:  [@Reload](https://discourse.cmake.org/u/Reload)
#### Post date: [November 21, 2023, 11:52am UTC](https://discourse.cmake.org/t/help-with-linking-snappy-to-leveldb-windows-pay-40/9472/10 "2023-11-21T11:52:26Z")
Clearly something’s wrong whl size only 98kb, with only leveldb ~200kb. And how did you link scappy to leveldb?
---
### Author:  [@retif](https://discourse.cmake.org/u/retif)
#### Post date: [November 21, 2023, 11:55am UTC](https://discourse.cmake.org/t/help-with-linking-snappy-to-leveldb-windows-pay-40/9472/11 "2023-11-21T11:55:28Z")
We can use personal messages here on the forum, I prefer not mix my identities 🙂
Also, this discussion might be of interest for others, so it’s worth keeping it public, at least until moderators would ask us to stop spamming.
I didn’t use those scripts, here are my steps:
```sh
$ cd /e/temp
$ mkdir some && cd $_
$ git clone --depth 1 git@github.com:google/snappy.git
$ git clone --depth 1 git@github.com:google/leveldb.git
$ git clone --depth 1 git@github.com:wbolster/plyvel.git
$ cd ./snappy
$ git rev-parse HEAD
27f34a580be4a3becf5f8c0cba13433f53c21337
$ mkdir build && cd build
$ cmake -G Ninja -DBUILD_SHARED_LIBS=1 -DCMAKE_POSITION_INDEPENDENT_CODE=1 -DCMAKE_WINDOWS_EXPORT_ALL_SYMBOLS=1 -DCMAKE_INSTALL_PREFIX="../install" -DSNAPPY_BUILD_TES
TS=0 -DSNAPPY_BUILD_BENCHMARKS=0 ..
$ cmake --build . --target install
$ cd ../../leveldb
$ git rev-parse HEAD
068d5ee1a3ac40dabd00d211d5013af44be55bea
$ mkdir build && cd build
$ cmake -G Ninja -DCMAKE_BUILD_TYPE=Release -DBUILD_SHARED_LIBS=1 -DCMAKE_POSITION_INDEPENDENT_CODE=1 -DLEVELDB_BUILD_TESTS=0 -DLEVELDB_BUILD_BENCHMARKS=0 -DCMAKE_INS
TALL_PREFIX="../install" -DCMAKE_PREFIX_PATH="e:/temp/some/snappy/install" ..
$ cmake --build . --target install
$ cd ../../plyvel
$ git rev-parse HEAD
fc99b8ebdd1e93ff53138c98bc3f90d786158cad
$ make
$ python setup.py bdist_wheel
$ du -hs ./dist/plyvel-1.5.0-cp311-cp311-win_amd64.whl
100K
$ pip install ./dist/plyvel-1.5.0-cp311-cp311-win_amd64.whl
```
Linking `snappy` from `leveldb` project:
```cmake
# ...
find_package(Snappy CONFIG REQUIRED)
if(Snappy_FOUND)
message(STATUS "Found Snappy: ${Snappy_DIR}")
endif()
include(CheckLibraryExists)
check_library_exists(crc32c crc32c_value "" HAVE_CRC32C)
# ugly, but they don't set usual variables for libraries discovery
check_library_exists(snappy snappy_compress "${Snappy_DIR}/../.." HAVE_SNAPPY)
check_library_exists(zstd zstd_compress "" HAVE_ZSTD)
check_library_exists(tcmalloc malloc "" HAVE_TCMALLOC)
message(STATUS "HAVE_SNAPPY: ${HAVE_SNAPPY}")
# ...
if(HAVE_SNAPPY)
target_link_libraries(leveldb Snappy::snappy)
endif(HAVE_SNAPPY)
# ...
```
Just in case, here’s `setup.py` modifications too:
```py
extra_compile_args = ['-Wall', '-g', '-x', 'c++', '-std=c++11', '-Ie:/temp/some/leveldb/install/include']
if platform.system() == 'Darwin':
extra_compile_args += ['-stdlib=libc++']
ext_modules = [
Extension(
'plyvel._plyvel',
sources=['plyvel/_plyvel.cpp', 'plyvel/comparator.cpp'],
library_dirs=["e:/temp/some/leveldb/install/lib"],
libraries=['leveldb'],
extra_compile_args=extra_compile_args
)
]
```
---
### Author:  [@retif](https://discourse.cmake.org/u/retif)
#### Post date: [November 21, 2023, 12:28pm UTC](https://discourse.cmake.org/t/help-with-linking-snappy-to-leveldb-windows-pay-40/9472/12 "2023-11-21T12:28:03Z")
…forgot to mention, in case it isn’t obvious, the path added with `os.add_dll_directory()` still needs to be discoverable (_be part of the `PATH`_), as this function seems to only “allow” loading from there, I don’t think it actually loads anything. And the path on your screenshot doesn’t look like it is part of the `PATH` (_unless you actually added it to PATH_).
In my case I was launching Python from the same working folder where the DLLs are, so they were discoverable.
---
### Author:  [@Reload](https://discourse.cmake.org/u/Reload)
#### Post date: [November 21, 2023, 12:30pm UTC](https://discourse.cmake.org/t/help-with-linking-snappy-to-leveldb-windows-pay-40/9472/13 "2023-11-21T12:30:56Z")
snappy - 1.1.9
leveldb - 1.22
```auto
cd snappy
cmake -DBUILD_SHARED_LIBS=ON -DCMAKE_POSITION_INDEPENDENT_CODE=on -DSNAPPY_BUILD_TESTS=0 -DSNAPPY_BUILD_BENCHMARKS=0 -DCMAKE_WINDOWS_EXPORT_ALL_SYMBOLS=ON .
cmake --build . --target install
cd levelbd
cmake -DCMAKE_BUILD_TYPE=Release -DBUILD_SHARED_LIBS=ON -DCMAKE_POSITION_INDEPENDENT_CODE=on -DLEVELDB_BUILD_TESTS=off -DLEVELDB_BUILD_BENCHMARKS=off .
cmake --build . --target install
Linking snappy: similarly ↑
leveldb.dll - 877kb
leveldb.lib - 82kb
scappy.dll - 199kb
scappy.lib - 181kb
plyenv setup.py
extra_compile_args = ['-Wall', '-g', '-x', 'c++', '-std=c++11', '-IC:\Program Files (x86)\leveldb\include']
if platform.system() == 'Darwin':
extra_compile_args += ['-stdlib=libc++']
ext_modules = [
Extension(
'plyvel._plyvel',
sources=['plyvel/_plyvel.cpp', 'plyvel/comparator.cpp'],
libraries=['leveldb'],
library_dirs=['C:\Program Files (x86)\leveldb\lib'],
extra_compile_args=extra_compile_args,
)
]
whl - 98kb
python code:
import os
os.add_dll_directory(r"C:\Users\xxx\PycharmProjects\xxx\libs")
import plyvel
class LevelDB:
def __init__ (self, path: str):
self._path = path
self._db = plyvel.DB(path)
def get_db(self):
with self._db.iterator() as it:
for k, v in it:
print(k, v)
def get_value(self, key: str):
return self._db.get(bytes(key, 'utf-8'))
leveldb = LevelDB("C:\\Users\\xxx\\Desktop\\leveldb\\test")
leveldb.get_db()
Warning - Cannot find reference 'DB' in ' __init__.py'
Error - Process finished with exit code -1073741819 (0xC0000005)
```
---
### Author:  [@Reload](https://discourse.cmake.org/u/Reload)
#### Post date: [November 21, 2023, 12:34pm UTC](https://discourse.cmake.org/t/help-with-linking-snappy-to-leveldb-windows-pay-40/9472/14 "2023-11-21T12:34:22Z")
I tried to run from the working directory, also added to the PATH, the result is the same
---
### Author:  [@Reload](https://discourse.cmake.org/u/Reload)
#### Post date: [November 21, 2023, 12:36pm UTC](https://discourse.cmake.org/t/help-with-linking-snappy-to-leveldb-windows-pay-40/9472/15 "2023-11-21T12:36:32Z")
– Building for: Visual Studio 17 2022
– Selecting Windows SDK version 10.0.22000.0 to target Windows 10.0.19045.
– The C compiler identification is MSVC 19.33.31630.0
– The CXX compiler identification is MSVC 19.33.31630.0
---
### Author:  [@retif](https://discourse.cmake.org/u/retif)
#### Post date: [November 21, 2023, 12:47pm UTC](https://discourse.cmake.org/t/help-with-linking-snappy-to-leveldb-windows-pay-40/9472/16 "2023-11-21T12:47:06Z")
Works for me:
```py
# ...
leveldb = LevelDB("e:/temp/testdb")
vals = leveldb.get_db()
#print(vals)
# added put_value() implementation
leveldb.put_value(b"key", b"ololo")
x = leveldb.get_value("key")
print(x)
# b'ololo'
```
My toolchain:
- Visual Studio 2022 17.7.5
- MSVC 19.37.32825.0
- Ninja 1.11.0
- CMake 3.25.1
---
### Author:  [@Reload](https://discourse.cmake.org/u/Reload)
#### Post date: [November 21, 2023, 12:52pm UTC](https://discourse.cmake.org/t/help-with-linking-snappy-to-leveldb-windows-pay-40/9472/17 "2023-11-21T12:52:38Z")
I don’t know what to do anymore…
---
### Author:  [@ben.boeckel](https://discourse.cmake.org/u/ben.boeckel)
#### Post date: [November 21, 2023, 1:36pm UTC](https://discourse.cmake.org/t/help-with-linking-snappy-to-leveldb-windows-pay-40/9472/18 "2023-11-21T13:36:59Z")
Getting ProcMon on the error detecting side of the system logs will help to determine what DLL is not being found.
---
### Author:  [@Reload](https://discourse.cmake.org/u/Reload)
#### Post date: [November 22, 2023, 10:59am UTC](https://discourse.cmake.org/t/help-with-linking-snappy-to-leveldb-windows-pay-40/9472/19 "2023-11-22T10:59:54Z")
---
### Author:  [@Reload](https://discourse.cmake.org/u/Reload)
#### Post date: [November 22, 2023, 11:02am UTC](https://discourse.cmake.org/t/help-with-linking-snappy-to-leveldb-windows-pay-40/9472/20 "2023-11-22T11:02:02Z")
I assume the problem is FILE LOCKED WITH ONLY READERS?
[Next page](https://discourse.cmake.org/t/help-with-linking-snappy-to-leveldb-windows-pay-40/9472.md?page=2)