OK. I have been very frustrated with the GMP for the past couple of hours. It seems that there is no default support for GMP library for Windows as they tend to target for Unix based systems. And also the tutorials that are found on the net are somewhat outdated, wasn’t written keeping the newcomers, like me, in mind or the newer tutorials are not on the first page of Google.
That said, I’ve finally been able to prepare it for windows. And I’m writing this just to help the others like me that may be searching solution to this problem and also for a future reference to myself for this and such other libraries as well. Let’s do it, shall we?
Getting the Library
First of all, we should get the library from gmplib.org. Current version is 5.0.4. The file may have been compressed twice. Extract it with a archive software like 7-zip. We have got the files that we need. We assume that we have extracted the folder here:
D:/C_Library/gmp-5.0.4
Now the next step should be to get MinGW.
Getting MinGW
We have to get MSYS. Since current version of MSYS can be obtained along with the MinGW. We shall download MinGW from their SourceForge Page. Let’s download it from there clicking the big green button. Now, when installing it, we should be careful to check MSYS so that we can use it. Otherwise the whole point of downloading MinGW becomes worthless. For me I checked everything. Since 401MB of space for a software seems too little these days (back in 2012 I was using a 30KBPs internet line in Dhaka). Default installation directory for this is thought to be
C:\MinGW
Using MSYS to build GMP
Now, from the directory where we have installed MinGW, we now look for msys folder. In this folder, there should be another folder only bearing a number (in current version it is 1.0). Inside that folder we should get msys.bat. That’s all we need. Now we run it. And get a command prompt like window. This is our Unix like environment for windows. The next step here would be to go to the directory where the necessary files for GMP are. Remember, our directory was simply D:/C_Library/gmp-5.0.4. So, on the MSYS window we now write,
cd /d/C_Library/gmp-5.0.4
and press Enter to go the gmp directory.
Legend says Unix is case sensitive, and turns out that this is certainly true and also there should be no spaces while writing the path (Now there there, as an experienced unix user I now know that you can use apostrophes around string of the path that includes spaces), but after cd there is a space. So we have to write the directory in proper case. We, should understand that /d/ is equivalent to D:\ in windows, and we have to use forward slash. Now, then we write in MSYS,
./configure --prefix=/d/C_Library/GMP --enable-cxx
and press Enter.
Now, let me shortly explain what it means. First of all you should see that there is a INSTALL.autoconf file the gmp-5.0.4 directory. So, we assume ./configure simply invokes INSTALL.autoconf file that may have the necessary instructions. And --prefix=/d/C_Library/GMP may mean we want the configured thing to be copied into the directory followed after the = sign. and --enable-cxx means it will create a header file for C++ envrinment too…
!! But we are not done yet!
Now we write in MSYS,
make
and press Enter as usual.
We wait for a couple of minutes…. Wait… Wait….
Now, I think we are already done with the above process. The next step is to write
make install
and press Enter.
Now, that was easy, isn’t? We now have several folders in the D:\C_Library\GMP folder. The include folder contains the header files gmp.h and gmpxx.h; and it is believed that for C we should use gmp.h and for C++ we should use gmpxx.h. And the lib folder contains the library files needed by the linker. We write
make check
to see it the header was build accordingly. After the test we should get there were no errors or something like that.
Using GMP with Code::Blocks
This is fairly easy. Open Code::Blocks. We can assume that we have Code::Blocks and it works with GCC compiler which is MinGW if we are on windows. But, since we now have a fresh MinGW installed in the C:\MinGW folder, we’ll use this fresh software with Code::Blocks from now on. Now, we open Code::Blocks ; click on Settings and then Compiler and Debugger….
From the Selected Compiler drop-down menu we choose GNU GCC Compiler.
Then we choose Toolchain Executables and set Compilers Installation Directory to C:\MinGW. I will upload a picture of this. This will make the next steps more clear as well.
So, this should look like this.
Next We select the tab Search directories. It it in the Compiler sub-tab we add the directory of the header files of our GMP library. In our case
D:\C_Library\GMP\include
and in the linker sub-tab we add
D:\C_Library\GMP\lib
Next what we do is we go to Linker Settings tab, and write libgmpxx.a and libgmp.a in the Linker libraries box in the sequence I wrote. This sequencing is important.
References or the links that helped me in this case a lot
GMP Install Instruction for Windows Platform
Using libraries with Code::Blocks
Original blog was posted in my personal blog. Now it has been posted in this site as well.