Ok, so, I'm trying to build a third party library with msys2 and I've run into a problem with a few headers, such as gtk.h; the library I'm trying to build expects this to be located via #include <gtk/gtk.h>.
Now, experience on Linux tells me that would be correct under a normal linux environment; however, in the case of gtk, it seems it would have to be gtk-3.0/gtk/gtk.h, which seems like an error in msys to me - is there some sort of selection step I've missed in setting up my msys2 environment? Like the 'eselect' system under Gentoo, something like 'pselect gtk-3.0' that would create a linked directory to gtk-3.0/gtk just called gtk?
Assuming that you have installed the mingw-w64-i686-gtk3 package with pacman and that you are running in a MinGW 32-bit shell (MSYS2 has three different flavors of shell that use different toolchains), you can run this command to get the required compile flags for GTK3:
pkg-config gtk+-3.0 --cflags
Most build systems have some kind of support for calling pkg-config. It is basically the standard way to get information about your dependencies.
When it's time to link your program, you should replace --cflags in the comand above with --libs.
You simply need to tell the compiler where to find the include directory:
-I/some/path/to/gtk-3.0
Related
I'm pretty new to C++ and I'm having a hard time trying to install external libraries. I want to get started with GUI programming and I have searched all over, but I cannot find a way to add wxWidgets to Code::Blocks. I've tried a few different guides and Stack Overflow responses but none of them have actually worked.
I'm using this 'Hello World!' test program to see if it works, every time I try to run it I just get this error: fatal error: wx/wxprec.h: No such file or directory. I can't seem to figure out how to tell Code::Blocks where the library is.
The most recent resource I have tried is this one, I followed it step by step, but still I got this error.
What linker/compiler settings do I need to use in Code::Blocks? What lib files do I need to add and where do I add them to? Do I need to build the .zip file? How do I do this?
Please could I get a step by step guide on exactly how to add wxWidgets (or indeed any external library) to Code::Blocks as well as some information on why certain things are required?
Here's what I tried
Following the steps in the link above, this is what I have in my build options:
I tried adding this in my global compiler settings...
I still have this error...
CodeBlocks seems to have some special wxWidgets integration, but it didn't always work for me, so I prefer to set up the project manually.
CB ships an outdated compiler. While it may work, updating it is a good idea.
Get rid of the MinGW version shipped with CB, or at least remove it from the PATH.
Install MSYS2. Use it to install a new GCC and GDB, as described in the link.
Configure CB to use MSYS2's GCC and GDB, by specifying the paths to them in the CB config (they're installed to C:\msys64\mingw64\bin).
wxWidgets seem to ship prebuilt libraries for MinGW, but since we're using MSYS2, we might as well use the version provided by MSYS2.
Use MSYS2 to install wxWidgets: pacman -S mingw-w64-x86_64-wxWidgets3.2-msw.
MSYS2 seems to ship several different versions of wxWidgets: 3.0, 3.1, 3.2, and each of them in two variants: -msw and -gtk. 3.2-msw looks like a reasonable choice to me, but I haven't used this library before.
wxWidgets doesn't seem to use the standard way of telling you what compiler flags to use (which would be pkg-config, or at least a CMake file). Instead they ship their own script to determine the flags, called wx-config.
Run wx-config --cflags to get the compiler flags, and run wx-config --libs to get the linker flags. Paste them into the project settings (compiler settings and linker settings respectively). Edit the project settings, not the global compiler settings.
I am asking here because I couldn't get any support elsewhere. Also consider that I am quite a beginner so bear patience.
I am using Winlibs (winlibs.com, a ready to use mingw gcc10+ distribution) to code under Windows because after having tried other alternatives I judged it the best to my purposes, easiest to install and the most functional. I never had any problems with it.
But recently I had the need of writing some simple code to send a POST request. I wanted to do it in a possibly portable and c++ friendly manner, so I was suggested to use Curl. No libcurl is included in winlibs so I tried to load one from here
https://curl.se/download.html
I chose the windows 64 binary of course (7.83.1) since I am working on windows 64 with winlibs 64. I installed everything in the right place and linked against libcurl.a.
Unfortunately the linker complains of unresolved symbols so I have to supppose the curl binaries I used are not suitable.
How can I use libcurl with winlibs then ? Before bothering here I really googled but could find no info!
The MinGW-w64 tools from https://winlibs.com/ are only a build toolchain, so they don't contain libraries for you to link with (yet).
You need a Windows build of libcurl and use that.
To use it you must include the location to the header files using the -I compiler flag, and then link with the library by pointing to the location of the .a file with the -L linker flag and then link with the library using the -l flag (-lcurl in this case). If you don't have .a files you can also try to link with the full path of the .dll file and gcc will know it's a shared library.
An easier way is to get libcurl via MSYS2's pacman package manager.
If you want to statically link you need to use the output of pkg-config --static --libs libcurl as link flags.
In practice though I noticed that sometomes pkg-config --static --libs libcurl is missing some dependencies and you still need to add some manually. An example of a project of mine that builds on Windows with winlibs MinGW-w64 (both 32-bit and 64-bit) can be found at https://github.com/brechtsanders/winlibs_tools/blob/main/Makefile (specifically look for the definition of CURL_LDFLAGS)
I am trying to compile a modelling program in Cygwin using either a gfortran or g95 compiler. I have installed both compilers, but when I go to configure the program, it checks for the compilers and does not find then (error: Fortran compiler cannot create executables). I am new to Cygwin-- I suspect it is something with how/where I installed the compilers...Any ideas?
Thank you,
L.
For me, it's more helpful to have executable code to go through the process, so I'm going to put some in. This is addressing your concern,
I suspect it is something with how/where I installed the compilers...
because the installation from apt-cyg should be helpful in letting the system know where to look for the compilers. I'm also addressing a possible linkage issue.
bballdave025#MY-MACHINE /cygdrive/c/bballdave025
$ apt-cyg install gcc-fortran libgfortran5
If you don't have apt-cyg yet, follow these instructions from another answer.
# Get to where your setup executable lives.
# This is what you used to install Cygwin the first time.
# Note that mine is for the 64-bit version, and that
# I keep mine in C:\cygwin64. Your path might be
# different. You also might need to re-download
# The setup executable from Cygwin.
$ cd /path/to/setup_install/setup_x86-64.exe -q -P wget
$ wget https://raw.githubusercontent.com/transcode-open/apt-cyg/master/apt-cyg
$ chmod +x apt-cyg
$ mv apt-cyg /usr/local/bin
The libgfortran5 (or a more recent version, if available when you search) might be necessary. Here's why I think this might be the case.
bballdave025#MY-MACHINE /cygdrive/c/bballdave025
$ man gcc | grep -A 3 "[ ]*[-]l[ ]\{0,2\}library$"
-llibrary
-l library
Search the library named library when linking. (The second
alternative with the library as a separate argument is only for
POSIX compliance and is not recommended.)
(Note that I haven't included some parts of the result that aren't useful and can be fixed by prefixing the command with MANWIDTH=160, cf here.)
There is a little more detail and a little different result from the answer to a question about the lib prefix on files:
You can name a library whatever you want, but if you want gcc's -l flag to find the right one, you need to name it the way that link describes. For example, gcc -o myapp myapp.c -lm, [w]ill compile myapp.c, link the resulting object with libm.a, and output an executable called myapp. These days, there might be a more complicated search path involving dynamic library names, etc., but you should get the basic idea from this example. [In addition, you can look at this section f]rom the gcc man page:
-l library ...
... surrounds library with lib and .a and searches several directories.
The basic reason for all of that info is this: it is very possible that, in order to link with the gfortran library, you need to have installed a package named something like libgfortran. I don't know for sure how this works, especially with the Cygwin man page being slightly different, but it's worth a try. The likely extra thing you would need in this case is something like
apt-cyg install libgfortran
or
apt-cyg install libgfortran5
Here's some helpful info on how I found what to install. When I had a similar problem, I went to the Cygwin package search, but I only got three entries with three versions of netcdf-fortran
(archived). I wanted gfortran, so I kept looking
I found a great gfortran answer in this SO answer. With that answer, I went back to the Complete Cygwin Package List, armed with my trusty Ctrl + F, since I knew there were packages different from what came back from the search. The complete list had
cygwin64-gcc-fortran GCC for Cygwin 64bit toolchain (Fortran)`
gcc-fortran GNU Compiler Collection (Fortran)
and entries for libgfortran.
Hopefully some of this information will be helpful, or at least educational.
This problem is common for beginners with autotools. It can be:
missing libraries; this can be missing libraries for your project or compiler/system libraries, like libgfortran or similar for g95.
autotools can not detect your compiler;
dynamic libraries problem; runtime path to the dynamic libraries not set. See LD_LIBRARY_PATH for linux environment.
cross-compiling problem, I do not know much about cygwin but that can be an issue. I am not expert of cross-compiling either. It can also be another situation that I am not aware of.
I ran into the 1st and 3rd situations.
Approaches of solutions.
make sure you can manually compile and run a simple hello world program. Install the missing libraries if necessary. Also make sure that you can link your hello world program against the same libraries used by your modelling program, this last statement could lead you to the 3rd situation.
add the path to your compiler to the PATH variable or similar variable in cygwin. Or explicitly give the full path to your compiler to configure.
add the path to your libraries to the runtime libraries path LD_LIBRARY_PATH for linux environment or similar variable in cygwin. In one of my cases, the problem was that the test program that autotools uses to test the compiler could not run. It was successfully compiled but could not run. I installed all the libraries that my project uses in a path that was not included in library path. What happened was that the path to those libraries were set in the configure.ac or makefile.am so that the compiling was OK. But the running of the test program included in configure could not find them. This is a problem mostly for dynamically linked libraries. Adding the path to my .so to the LD_LIBRARY_PATH solved the problem.
well, I can not really help. The only solution that I can suggest is to install a linux system (dual boot or virtual machine) if you know how to do it, because I will not be there to help.
The following link can also help.
I want to use openssl library in my NaCl module. Luckily it is ported already as in https://code.google.com/p/naclports/. However, its kind of pity but I don't know how to add the library to the toolchain. I did as instructed in the Readme file:
...nacl_sdk/pepper_33/naclports/src$ python build_tools/naclports.py install openssl
Already installed 'openssl' [x86_64/newlib]
And then I tried to compile this simple C code, and the compiler complaint some errors which are because of linking problem with openssl/evp.h.
This is my Makefile: link. Please let me know how to make it run.
NaCl actually consists of several different toolchains. naclports will build and install a given library to just one of them at time. The libraries and headers get installed directly into the toolchain so there is no need to -L or -I on the command line.
In this case you have built and installed the x86_64 newlib version of openssl. This means that you should be able to build the x86_64 newlib version of your app (add TOOLCHAIN=newlib NACL_ARCH=x86_64 to your make call).
To build all the other versions of openssh you can use the "make_all.sh" script at the top level of naclports (e.g. ./make_all.sh openssl).
Build naclports. Look in naclports/README.rst for instructions.
All I need is get MinGW talking to Postgres. I've considered several options:
Use libpq. The libpq.lib that comes with Postgres for Windows links okay, but crashes when I use the library. I think because it was compiled for VC++. I can't find just the libpq code, so I'd have to recompile the entire Postgres tree in MinGW. Not easy.
Use libpqxx. Requires libpq!
Use libodbcxx. Requires some sort of ODBC manager like iodbc. Maybe I can use iodbc directly. Since this is just Windows for now can I use -lodbc on my linker and use some Windows specific commands?
Option 1 sounds the least painful. I'm pretty sure the project will use Postgres, not too sure if the project will stay on Windows. Is there a simple way to get this functionality?
You can rebuild just libpq if you have to. Run "./configure" and then run "make" in just src/interfaces/libpq.
But really, the msvc built libpq should work just fine with mingw. It's just a standard Windows DLL. It may be an issue with the .lib - but the DLL should be fine. AFAIK, only the PQtrace() functionality will be broken - because of the way MSVCRT works, that only works if you have the exact same version of the runtime.
You should also be able to generate an import library directly off the DLL, if the .LIB doesn't work. Or does MingW even allow you to link directly to the DLL - see their wiki
Getting libpq to work is likely a lot easier than odbc.
As you also asked R questions here, I assume you can manage to read source to R packages. The RPostgreSQL package does exactly what you are after:
It uses MinGW as all R binaries and packages on Windows are built with MinGW
It links to libpq to talk to Postgres
The file src/Makevars.win simply has
PKG_CPPFLAGS=-I"${PG_HOME}"/include
PKG_LIBS=-L"${PG_HOME}"/lib -llibpq
which tells R where the Pg headers and library are, and then links with libpq.
A side-note... Your CXXFLAGS and LDFLAGS for compiling and linking to the Postgres files can be setup easily using the following variables in your Makefile:
CXXFLAGS += -I$(shell pg_config --includedir)
LDFLAGS += -L$(shell pg_config --libdir) -llibpq
(Provided you have included the bin folder that contains pg_config.exe of your PostgreSQL installation on your system's PATH and that you use mingw32-make.)