I decided to write a short tutorial where I’m going to explain how I  built the rtlsdr software on windows x64 from source… why? After a crash of my personal linux laptop I had to come back to windows installed on the laptop I use at work. Now I have only it, but I want to continue using rtl-sdr! Unfortunately, on rtl-srd site the “windows” aspect is not much supported and it shows only a link to pre-built version. My nerd-side used this built rtl-sdr  with stupid suspicious (because, at the end, everything works fine) and after some days the nerd-side won and I decided to recompile the rtl-sdr from scratch.

I did not find any tutorial which explains this task and so I decided to write a short tutorial where I’ll explain how I recompiled the rtlsdr software on windows x64 from source.

What is RTL-SDR?

First of all, what is the rtl-sdr? I want to explain it quoting the beautiful site rtl-sdr.com:

RTL-SDR is a very cheap software defined radio that uses a DVB-T TV tuner dongle based on the RTL2832U chipset. With the combined efforts of Antti Palosaari, Eric Fry and Osmocom it was found that the signal I/Q data could be accessed directly, which allowed the DVB-T TV tuner to be converted into a wideband software defined radio via a new software driver.

More information on http://www.rtl-sdr.com/about-rtl-sdr/ or http://sdr.osmocom.org/trac/wiki/rtl-sdr site.

Precondition

This is my environment to recompile the rtl-sdr. It is mandatory to have these tools installed on  your system:

• Source Versioning – GIT ( http://msysgit.github.io )
• Compiler – MinGW-w64 the GCC for both x64 & x86 Windows (http://mingw-w64.sourceforge.net/ )
• CMake – http://www.cmake.org/

The rtl-sdr compilation uses libusb1.0 library and  pthreads. I used the following versions for them:

• libusb1.0 – Following the link present on site libusb.org you can find newer release binary as part of libusbx releases.
• pthreads – I use the pthreads-win32, but the main repository has a broken link, so I used a mirror site to dowload it.

Compile

To compile I cloned the source repository:

Z:>git clone git://git.osmocom.org/rtl-sdr.git
 Cloning into 'rtl-sdr'...
 remote: Counting objects: 1277, done.
 remote: Compressing objects: 100% (371/371), done.
 remote: Total 1277 (delta 931), reused 1220 (delta 898)
 Receiving objects: 100% (1277/1277), 275.08 KiB | 161.00 KiB/s, done.
 Resolving deltas: 100% (931/931), done.

and I built the environment (unzip/ungzip the library) and put it into a directory named libs. Now, the structure of my working dir is:

Z:>dir /S
 Volume in drive Z is New Volume
 Volume Serial Number is 82D1-DF30

 Directory of Z:\015

16/10/2013  12:51    <DIR>          .
16/10/2013  12:51    <DIR>          ..
16/10/2013  12:44    <DIR>          libs
16/10/2013  12:48    <DIR>          rtl-sdr
               0 File(s)              0 bytes

 Directory of Z:libs

16/10/2013  12:44    <DIR>          .
16/10/2013  12:44    <DIR>          ..
16/10/2013  12:43    <DIR>          libusbx-1.0.17
16/10/2013  12:44    <DIR>          pthreads-w32-2-9-1-release
               0 File(s)              0 bytes
[...]

The next step is to configure cMake to compile the source. On *nix system it exists a useful software called pkg-tool. It resolves all problem for command line library parameters, but on windows I don’t know an equivalent tool. So, I must set manually these parameters on CMake and I used the gui of CMake to set them.

In order:

• load the command line with mingw64 parameters ( ex C:…x64-4.8.1-posix-seh-rev5mingwbuilds.bat )
• create a new directory named “build” into “rtl-sdr” folder
• on folder “build” type the command “cmake-gui”

A new window is opened, it’s the CMake configurator. Into this window I set the flag “advanced” and I  opened the dialog for compiler configuration via “Tools” > “Config”. In this dialog window I set the compilers paths of.

When you save the configuration, CMake tries to generate the config file but this error occurs:

The C compiler identification is GNU 4.8.1
 Check for working C compiler: C:/Program Files/mingw-builds/x64-4.8.1-posix-seh-rev5/mingw64/bin/x86_64-w64-mingw32-gcc.exe
 Check for working C compiler: C:/Program Files/mingw-builds/x64-4.8.1-posix-seh-rev5/mingw64/bin/x86_64-w64-mingw32-gcc.exe -- works
 Detecting C compiler ABI info
 Detecting C compiler ABI info - done
 Build type not specified: defaulting to release.
 Extracting version information from git describe...
 Could NOT find PkgConfig (missing: PKG_CONFIG_EXECUTABLE)
 libusb-1.0 not found.
 Could NOT find Threads (missing: THREADS_PTHREADS_WIN32_LIBRARY THREADS_PTHREADS_INCLUDE_DIR)
 CMake Error at CMakeLists.txt:67 (message):
 LibUSB 1.0 required to compile rtl-sdr
 Configuring incomplete, errors occurred!

It’s easy, CMake doesn’t find the libraries and we have to indicate them on Name/Value panel. So, I inserted the following information:

CMAKE_GNUtoMS:BOOL=1
PKG_CONFIG_EXECUTABLE:FILEPATH=PKG_CONFIG_EXECUTABLE-NOTFOUND
CMAKE_AR:FILEPATH=C:/Program Files/mingw-builds/x64-4.8.1-posix-seh-rev5/mingw64/bin/ar.exe
CMAKE_STRIP:FILEPATH=C:/Program Files/mingw-builds/x64-4.8.1-posix-seh-rev5/mingw64/bin/strip.exe
CMAKE_MAKE_PROGRAM:FILEPATH=C:/PROGRA~1/MINGW-~1/X64-48~1.1-P/mingw64/bin/mingw32-make.exe
GIT_EXECUTABLE:FILEPATH=C:/Program Files (x86)/Git/cmd/git.exe
CMAKE_USE_RELATIVE_PATHS:BOOL=1
CMAKE_C_STANDARD_LIBRARIES:STRING=-lws2_32 -lkernel32 -luser32 -lgdi32 -lwinspool -lshell32 -lole32 -loleaut32 -luuid -lcomdlg32 -ladvapi32 
LIBUSB_INCLUDE_DIR:PATH=Z:/libs/libusb-1.0.17/include/libusbx-1.0
LIBUSB_LIBRARIES:FILEPATH=Z:/libs/libusb-1.0.17/MinGW64/static/libusb-1.0.a
THREADS_PTHREADS_INCLUDE_DIR:PATH=Z:/libs/pthreads-w32-2-9-1-release/Pre-built.2/include
THREADS_PTHREADS_WIN32_LIBRARY:FILEPATH=Z:/libs/pthreads-w32-2-9-1-release/Pre-built.2/lib/x64/pthreadVC2.lib

That’s all, now we can run the configure and generate command to build all make files. After closing the cmake-gui on command line,  we can start the compilation and everything is ok!

Is it really everything ok?

Emmh… in my checkout (trunk) I started the compilation with the command mingw32-make.exe but I had this problem:

I asked info on mailing list for this error:

....src
tl_tcp.c: In function 'gettimeofday':
....src
tl_tcp.c:112:10: error: invalid suffix "Ui64" on integer constant
   tmp -= 11644473600000000Ui64;
          ^
srcCMakeFiles
tl_tcp.diruild.make:57: recipe for target 'src/CMakeFiles/rtl_tcp.dir/rtl_tcp.c.obj' failed
mingw32-make.exe[2]: *** [src/CMakeFiles/rtl_tcp.dir/rtl_tcp.c.obj] Error 1
CMakeFilesMakefile2:319: recipe for target 'src/CMakeFiles/rtl_tcp.dir/all' failed
mingw32-make.exe[1]: *** [src/CMakeFiles/rtl_tcp.dir/all] Error 2
Makefile:115: recipe for target 'all' failed
mingw32-make.exe: *** [all] Error 2

and the mailing list helped me to solve immediately the problem, I’ll quote the answer below:

It looks like the “i64” suffix is specific to Microsoft VC++.  I guess since you’re compiling for Windows it’s assumed you’ll be using the MS compiler.  Try changing the “Ui64” at the end of the number to the standard “ULL” instead and see if that lets you finish compiling.

So, I replaced Ui64 with ULL and now really everything compiles!