A lesson from my misusing command line options

[kLiHz]

Note: After some investgation, I realize that this has nothing to do with the build process, but something associated with PowerShell. Sorry for the disturbance!

And I should have realized this earlier when seeing pwsh's highlighting:

So the proper way to pass a decimal might be like -a="1.234".

I was trying to make use of OpenCV's cv::CommandLineParser. According to OpenCV's doc about cv::CommandLineParser, built from the following code should, the executable should parse command line options like:

$ ./cli_parse.exe -a=0.45 -B=0.38
a: 0.45; b: 0.38

And it works just right while using MSYS2's MinGW-w64-x86_64 toochain (MinGW gcc and OpenCV 4.2). However when I try to build it using vcpkg's toolchain with MSVC 17(Visual Studio 2022 Preview, host amd64, targeting amd64), the executable works (in pwsh7) as below:

PS> .\cli_parse.exe -a=0.45 -B=0.38
a: 0; b: 0
PS> .\cli_parse.exe --a=0.45 --B=0.38
a: 0.45; b: 0.38

My vcpkg OpenCV installed features (also build with Visual Studio 2022 Preview):

opencv4[core,dnn,eigen,ffmpeg,ipp,jpeg,openmp,png,qt,quirc,tiff,webp]:x64-windows -> 4.5.3#3

C++ source file:

// cli_parse.cpp

#include <opencv2/core/utility.hpp>
#include <iostream>

int main(int argc, char *argv[]) {
    auto keys = 
        "{help h ?   |     | Print this message           }"
        "{a weight-a | 0.5 | Weight of sth; default 0.5   }"
        "{B weight-b | 0.5 | Weight of sth; default 0.5   }";
    
    cv::CommandLineParser parser(argc, argv, keys);
    parser.about("OpenCV Command-line Parser Test v1.0.0");
    
    if (parser.has("help")) {
        parser.printMessage();
        return 0;
    }
    
    auto a = parser.get<double>("a");
    auto b = parser.get<double>("B");

    if (!parser.check()) {
        parser.printMessage();
        parser.printErrors();
        return 0;
    }
    
    std::cout << "a: "<< a  << "; b: " << b << "\n";

    return 0;
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.13)
project(opencv_test)

set(CMAKE_CXX_STANDARD 17)

find_package(OpenCV REQUIRED)

add_executable(cli_parse cli_parse.cpp)
target_link_libraries(cli_parse ${OpenCV_LIBS})

The extra CMake options I used when building this demo are:

-DCMAKE_WINDOWS_EXPORT_ALL_SYMBOLS=TRUE
-DCMAKE_EXPORT_COMPILE_COMMANDS:BOOL=TRUE
-T host=x64 -A x64