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Interfacing KDB+ with C

This project demonstrates how to marshall data between kdb+ and C using the Kx provided interface. A shared object is built as the output and a q script is provided that will show how to load the C functions into kdb+ dynamically.

The PDF documentation for this resource can be found here and also on the AquaQ Analytics website.

Installation & Setup

Extra Resources

You will need to download the q.lib file from the repository for Windows platforms and place it in the w32/ directory.

This project uses CMake 2.6+ to build across multiple platforms. It has been tested on Linux and Windows. Execute the following commands on all platforms to create platform appropriate build files within the build directory.

mkdir build; cd build; cmake ..

Building on Linux

On Linux, you just need to run make install to complete the build process and find the binary output in the ../bin directory.

make install && cd ../bin

Building on Windows

On Windows platforms you will need to have the msbuild.exe available on your path. CMake creates two Visual Studio projects that need to be built. The INSTALL project will not modify any of the code and will just move the binaries from the ../build directory to the ../bin directory. An extra libqtoc.lib file will be produced on Windows, which can be ignored after the build process.

msbuild ./ALL_BUILD.vcxproj /p:Configuration=Release
msbuild ./INSTALL.vcxproj /p:Configuration=Release
cd ../bin

Running the Examples

The resulting directory after running a build should look like this:

bin/                    -- contains the libqtoc.[dll/so] library and makeprint.q
build/                  -- contains the makefile/visual studio projects
src/                    -- contains the source code

Once the build is complete, navigate to the bin directory and execute:

q makeprint.q

This will load the C shared object and bind the functions to names (make and print). Instructions and example commands should be displayed as soon as the the makeprint.q script loads.

# makeprint.q
# Example q script that loads in two functions from the libqtoc shared object
# and makes them available as 'make' and 'print'.
# AquaQ Analytics
# kdb+ consultancy, training and support
# For questions, comments, requests or bug reports, please contact us
# w:
# e:
# examples:
#       print[1b] to print an atom
#       print[101b] to print a list
#       print[`a`b`c!1 2 3] to print a dictionary]
#       print[([] a:til 5; b:reverse `char$65+til 5)] to print a table
#       make[`b] to create a atom
#       make[`B] to create a list
#       make[`dictionary] to create a dictionary
#       make[`table] to create a table
q) print[`a`b`c!1 2 3]
a   | 1
b   | 2
c   | 3
q) make[`M]
2011.12 2014.05 2019.05 2018.07 2012.09m

Other Resources

This resource is intended to suppliment the existing Kx Wiki sections on interfacting with C and provide some concrete examples. Readers should look at the following pages on the Kx Wiki:


Some example code for interfacing with kdb+ from C






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