Windows 10 CMake | OPENCV_EXTRA_MODULES_PATH | Bug

[ashuezy]

• OpenCV => Latest Github
• Operating System / Platform => Windows 64 Bit
• Compiler => Visual Studio 2015

CMake Error at cmake/OpenCVModule.cmake:368 (_glob_locations):
  Syntax error in cmake code at

    E:/opencv_github/opencv/cmake/OpenCVModule.cmake:368

  when parsing string

    E:\opencv_github\opencv_contrib\modules

  Invalid character escape '\o'.
Call Stack (most recent call first):
  modules/CMakeLists.txt:7 (ocv_glob_modules)

This error is only generated when i set OPENCV_EXTRA_MODULES_PATH,
I have set the path to the modules folder after taking checkout of opencv_contrib.

[alalek]

Use forward slash ('/') in paths, even on Windows.

[ashuezy]

set(the_description "Face recognition etc")
ocv_define_module(face opencv_core
    opencv_imgproc
    opencv_objdetect
    opencv_video     # estimateRigidTransform() (trainFacemark)
    opencv_photo     # seamlessClone() (face_swap sample)
    WRAP python java
)
# NOTE: objdetect module is needed for one of the samples

set(__commit_hash "8afa57abc8229d611c4937165d20e2a2d9fc5a12")
set(__file_hash "7505c44ca4eb54b4ab1e4777cb96ac05")
ocv_download(
    FILENAME face_landmark_model.dat
    HASH ${__file_hash}
    URL
      "${OPENCV_FACE_ALIGNMENT_URL}"
      "$ENV{OPENCV_FACE_ALIGNMENT_URL}"
      "https://raw.githubusercontent.com/opencv/opencv_3rdparty/${__commit_hash}/"
    DESTINATION_DIR "${CMAKE_BINARY_DIR}/${OPENCV_TEST_DATA_INSTALL_PATH}/cv/face/"
    ID "data"
    RELATIVE_URL
    STATUS res
)
if(NOT res)
  message(WARNING "Face: Can't get model file for face alignment.")
endif()

The only slash 'o' is the url.

[alalek]

Problem is here:

E:\opencv_github\opencv_contrib\modules
E: => \o <= pencv_github => \o <= pencv_contrib\modules

[alalek]

BTW, What is CMake version used?

[ashuezy]

@alalek
3.10.0

[kinchungwong]

Unfortunately, CMake places this responsibility on the CMake script maintainers. See TO_CMAKE_PATH and TO_NATIVE_PATH

https://stackoverflow.com/questions/47910256/cmake-how-to-normalize-paths
https://stackoverflow.com/questions/32585927/proper-way-to-use-platform-specifc-spearators-in-cmake

[ashuezy]

@kinchungwong
What i can do i solve this on my system ?

[alalek]

As workaround try to run cmake with '/' in paths:

cmake -DOPENCV_EXTRA_MODULES_PATH=E:/opencv_github/opencv_contrib/modules ...

[ashuezy]

@alalek

I am using windows.

[alalek]

Unfortunately we don't observe these problems with Windows:
http://pullrequest.opencv.org/buildbot/builders/3_4-contrib-win64-vc14/builds/14/steps/cmake/logs/stdio

Message blames on this line:
https://github.com/opencv/opencv/blame/0f298a42032798d2d83017030621fcba885a3372/cmake/OpenCVModule.cmake#L368

with "syntax error", but syntax itself is correct.

Related CMake bug: https://gitlab.kitware.com/cmake/cmake/issues/17382
It is closed, but their "fix" doesn't fix problem with CMake's "syntax error".
Issue's reproducer just ignored and still reproducible with at least CMake 3.10.2.

[ashuezy]

@alalek
Is there ANY solution ,.. get around for the time being ?

[alalek]

Workaround: #11655 (comment)

I can't propose something else because I can't reproduce the problem on machines from my side.

[csukuangfj]

@ashuezy
/ is also supported on the Windows platform.

[mworchel]

I just compiled the latest OpenCV version on Windows 10 64-bit with contributor modules, it works fine.
@ashuezy You maybe misunderstood what the others meant: You have to replace every \ in the path with a /.

[rkachach]

I got the same error using an incorrect path for modules. Just in case somebody runs in the same problem ..

[seaweedseed]

Though I got the same error at first, after changing my directory(which contains "opencv" and "opencv_contrib") from D: to C: , it worked fine. I don't know why...

If I have any mistakes, just tell me plz.

• opencv => 4.0
• opencv_contrib => 4.0.0
• Operating System / Platform => Windows 64 Bit
• Compiler => Visual Studio 15 2017

[marianojj]

I was able to solve this problem by inverting the address bars of the folder
C:\Users\MyUser\OpenCv\opencv_contrib-4.3.0\modules to C:/Users/MyUser/OpenCv/opencv_contrib-4.3.0/modules
If you are using cmake gui you can navigate to the folder using
the option (...) in the space reserved for the value in OPENCV_EXTRA_MODULES_PATH, this brings the bars in the right format for the cmake.
I hope this helps, it worked for me.

[Ilan-peled]

Any mistake in the path gives this error. My mistake was:
I entered C:/Users/MyUser/OpenCv/opencv_contrib-4.3.0/
instead of C:/Users/MyUser/OpenCv/opencv_contrib-4.3.0/modules