I am new to Rust, so excuse me if im just doing things horribly wrong.
While larning the language i wanted to try out different bindings of libraries that i already used in other languages, amongst them SDL2, SFML2, Gtk3.
To my surprise, nothing seemed to work out of the box. They all depend on C libraries and those don't come with the cargo crate. I managed to get SFML2 to work after following the readme and manually copying .lib and .dll files to the right places. I tried to make the Rust linker to look into my vcpk directory for .lib files, sadly with no success.
The whole point of a package manager kind of is to automate these things for you. Other package managers like NuGet for C# dont require you to manually fiddle the dependencies for their packages together.
Getting rid of the thirdparty library management hell of C/C++ was one of the reasons why i took a closer look at Rust.
Am i doing something wrong, or is this just how things are with Rust/Cargo?
Cargo is a build management and source package management tool for Rust code - it is not a tool for managing binaries or compiling other languages such as C or C++.
Having said that, it is a very flexible tool so it is possible for crates that provide bindings to libraries written in other languages to "bundle" the libraries they depend on.
The Rust-SDL2 crate, for example, does offer such a feature - as it says in their README:
Since 0.31, this crate supports a feature named "bundled" which
downloads SDL2 from source, compiles it and links it automatically.
To use this, you would would add it to your Cargo.toml like this:
[dependancies]
sdl2 = { version = "0.34.0", features=["bundled"] }
Not all such binding crates support bundling, especially if the libraries they bind to are large, complex, have lots of their own dependencies and/or have lots of compile time configuration options.
In those cases you will either need to install a pre-compiled binary, or compile them from source yourself.
Perhaps it's just better to describe my problem.
I'm developing a Haskell library. But part of the library is written in C, and another part actually in raw LLVM. To actually get GHC to spit out the code I want I have to follow this process:
Run ghc -emit-llvm on both the code that uses the Haskell module and the "Main" module.
Run clang -emit-llvm on the C file
Now I've got three .ll files from above. I add the part of the library I've handwritten in raw LLVM and llvm-link these into one .ll file.
I then run LLVM's opt on the linked file.
Lastly, I feed the LLVM bitcode fileback into GHC (which pleasantly accepts it) and produces an executable.
This process (with appropriate optimisation settings of course) seems to be the only way I can inline code from C, removing the function call overhead. Since many of these C functions are very small this is significant.
Anyway, I want to be able to distribute the library and for users to be able to use it as painlessly as possible, whilst still gaining the optimisations from the process above. I understand it's going to be a bit more of a pain than an ordinary library (for example, you're forced to compile via LLVM) but as painlessly as possible is what I'm looking for advice for.
Any guidance will be appreciated, I don't expect a step by step answer because I think it will be complex, but just some ideas would be helpful.
If I have a package with several executables, which I initially build using cabal build. Now I change one file that impacts just one executable, cabal seems to take about a second or two to examine each executable to see if it's impacted or not. On the other hand, make, given an equivalent number of executables and source files, will determine in a fraction of a second what needs to be recompiled. Why the huge difference? Is there a reason, cabal can't just build its own version of a makefile and go from there?
Disclaimer: I'm not familiar enough with Haskell or make internals to give technical specifics, but some web searching does offer some insight that lines up with my proposal (trying to avoid eliciting opinions by providing references). Also, I'm assuming your makefile is calling ghc, as cabal apparently would.
Proposal: I believe there could be several key reasons, but the main one is that make is written in C, whereas cabal is written in Haskell. This would be coupled with superior dependency checking from make (although I'm not sure how to prove this without looking at the source code). Other supporting reasons, as found on the web:
cabal tries to do a lot more than simply compiling, e.g. appears to take steps with regard to packaging (https://www.haskell.org/cabal/)
cabal is written in haskell, although the run time is written in C (https://en.wikipedia.org/wiki/Glasgow_Haskell_Compiler)
Again, not being overly familiar with make internals, make may simply have a faster dependency checking mechanism, thereby better tracking these changes. I point this out because from the OP it sounds like there is a significant enough difference to where cabal may be doing a blanket check against all dependencies. I suspect this would be the primary reason for the speed difference, if true.
At any rate, these are open source and can be downloaded from their respective sites (haskell.org/cabal/ and savannah.gnu.org/projects/make/) allowing anyone to examine specifics of the implementations.
It is also likely one could see a lot of variance in speed based upon the switches passed to the compilers in use.
HTH at least point you in the right direction.
Recently I'm trying to build and use libharu library in order to create PDFs from bitmaps.
I've made some research trough it's site : http://libharu.org/.
There are instructions showing how to build it, but i doesn't build because it has dependencies to two other libraries(which i don't understand how to integrate in the building process) - zlib and libpng.
But i cant understand clearly the entire process so my last hope is if someone has built it from scratch and could explain me or provide me with some details for the building process.
LibHaru was forked after 2.0.8. The later version uses a make system whose code seems to have changed. First of the new variant was 2.10.0. Old version is on sourceforge.
I couldn't get later version to compile but 2.0.8 worked. (dated 2006) In the past I have seen comment suggesting I am not alone. You are correct there are no instructions about the dependencies. If you can you should use the pre-built version, which is mentioned.
From your message I assume you have little software building experience. Outlining in a few words if not feasible, here is a little. Dependent libraries have to be available, either as source for compiling, or occasionally as pre-built libraries specifically for the compiler/OS you are using. You have to go and get them. Then the compiler system you are using to build libharu, has to be able to "see" the dependent libraries, in this case the *.h file. After compiling the whole lot has to be linked together. None of this is rocket science but is a major source of frustration, everything has to be just right, usually with nothing to tell you what is wrong.
And that is why some people favor using a third party "build" tool. If it works.
libharu has two major dependencies: zlib and libpng, both widely used libraries which usually compile easily but I think there are ways to omit these for a loss of functionality, are about handling import of bitmaps.
So you have three sets of sources and essentially three libraries where as a final step are linked to from the libharu source code.
Alternatively you could find a pre-built version.
Recently, I switched my development environment from Windows to Linux. So far, I have only used Visual Studio for C++ development, so many concepts, like make and Autotools, are new to me. I have read the GNU makefile documentation and got almost an idea about it. But I am kind of confused about Autotools.
As far as I know, makefiles are used to make the build process easier.
Why do we need tools like Autotools just for creating the makefiles? Since all knows how to create a makefile, I am not getting the real use of Autotools.
What is the standard? Do we need to use tools like this or would just handwritten makefiles do?
You are talking about two separate but intertwined things here:
Autotools
GNU coding standards
Within Autotools, you have several projects:
Autoconf
Automake
Libtool
Let's look at each one individually.
Autoconf
Autoconf easily scans an existing tree to find its dependencies and create a configure script that will run under almost any kind of shell. The configure script allows the user to control the build behavior (i.e. --with-foo, --without-foo, --prefix, --sysconfdir, etc..) as well as doing checks to ensure that the system can compile the program.
Configure generates a config.h file (from a template) which programs can include to work around portability issues. For example, if HAVE_LIBPTHREAD is not defined, use forks instead.
I personally use Autoconf on many projects. It usually takes people some time to get used to m4. However, it does save time.
You can have makefiles inherit some of the values that configure finds without using automake.
Automake
By providing a short template that describes what programs will be built and what objects need to be linked to build them, Makefiles that adhere to GNU coding standards can automatically be created. This includes dependency handling and all of the required GNU targets.
Some people find this easier. I prefer to write my own makefiles.
Libtool
Libtool is a very cool tool for simplifying the building and installation of shared libraries on any Unix-like system. Sometimes I use it; other times (especially when just building static link objects) I do it by hand.
There are other options too, see StackOverflow question Alternatives to Autoconf and Autotools?.
Build automation & GNU coding standards
In short, you really should use some kind of portable build configuration system if you release your code to the masses. What you use is up to you. GNU software is known to build and run on almost anything. However, you might not need to adhere to such (and sometimes extremely pedantic) standards.
If anything, I'd recommend giving Autoconf a try if you're writing software for POSIX systems. Just because Autotools produce part of a build environment that's compatible with GNU standards doesn't mean you have to follow those standards (many don't!) :) There are plenty of other options, too.
Edit
Don't fear m4 :) There is always the Autoconf macro archive. Plenty of examples, or drop in checks. Write your own or use what's tested. Autoconf is far too often confused with Automake. They are two separate things.
First of all, the Autotools are not an opaque build system but a loosely coupled tool-chain, as tinkertim already pointed out. Let me just add some thoughts on Autoconf and Automake:
Autoconf is the configuration system that creates the configure script based on feature checks that are supposed to work on all kinds of platforms. A lot of system knowledge has gone into its m4 macro database during the 15 years of its existence. On the one hand, I think the latter is the main reason Autotools have not been replaced by something else yet. On the other hand, Autoconf used to be far more important when the target platforms were more heterogeneous and Linux, AIX, HP-UX, SunOS, ..., and a large variety of different processor architecture had to be supported. I don't really see its point if you only want to support recent Linux distributions and Intel-compatible processors.
Automake is an abstraction layer for GNU Make and acts as a Makefile generator from simpler templates. A number of projects eventually got rid of the Automake abstraction and reverted to writing Makefiles manually because you lose control over your Makefiles and you might not need all the canned build targets that obfuscate your Makefile.
Now to the alternatives (and I strongly suggest an alternative to Autotools based on your requirements):
CMake's most notable achievement is replacing AutoTools in KDE. It's probably the closest you can get if you want to have Autoconf-like functionality without m4 idiosyncrasies. It brings Windows support to the table and has proven to be applicable in large projects. My beef with CMake is that it is still a Makefile-generator (at least on Linux) with all its immanent problems (e.g. Makefile debugging, timestamp signatures, implicit dependency order).
SCons is a Make replacement written in Python. It uses Python scripts as build control files allowing very sophisticated techniques. Unfortunately, its configuration system is not on par with Autoconf. SCons is often used for in-house development when adaptation to specific requirements is more important than following conventions.
If you really want to stick with Autotools, I strongly suggest to read Recursive Make Considered Harmful (archived) and write your own GNU Makefile configured through Autoconf.
The answers already provided here are good, but I'd strongly recommend not taking the advice to write your own makefile if you have anything resembling a standard C/C++ project. We need the autotools instead of handwritten makefiles because a standard-compliant makefile generated by automake offers a lot of useful targets under well-known names, and providing all these targets by hand is tedious and error-prone.
Firstly, writing a Makefile by hand seems a great idea at first, but most people will not bother to write more than the rules for all, install and maybe clean. automake generates dist, distcheck, clean, distclean, uninstall and all these little helpers. These additional targets are a great boon to the sysadmin that will eventually install your software.
Secondly, providing all these targets in a portable and flexible way is quite error-prone. I've done a lot of cross-compilation to Windows targets recently, and the autotools performed just great. In contrast to most hand-written files, which were mostly a pain in the ass to compile. Mind you, it is possible to create a good Makefile by hand. But don't overestimate yourself, it takes a lot of experience and knowledge about a bunch of different systems, and automake creates great Makefiles for you right out of the box.
Edit: And don't be tempted to use the "alternatives". CMake and friends are a horror to the deployer because they aren't interface-compatible to configure and friends. Every half-way competent sysadmin or developer can do great things like cross-compilation or simple things like setting a prefix out of his head or with a simple --help with a configure script. But you are damned to spend an hour or three when you have to do such things with BJam. Don't get me wrong, BJam is probably a great system under the hood, but it's a pain in the ass to use because there are almost no projects using it and very little and incomplete documentation. autoconf and automake have a huge lead here in terms of established knowledge.
So, even though I'm a bit late with this advice for this question: Do yourself a favor and use the autotools and automake. The syntax might be a bit strange, but they do a way better job than 99% of the developers do on their own.
For small projects or even for large projects that only run on one platform, handwritten makefiles are the way to go.
Where autotools really shine is when you are compiling for different platforms that require different options. Autotools is frequently the brains behind the typical
./configure
make
make install
compilation and install steps for Linux libraries and applications.
That said, I find autotools to be a pain and I've been looking for a better system. Lately I've been using bjam, but that also has its drawbacks. Good luck finding what works for you.
Autotools are needed because Makefiles are not guaranteed to work the same across different platforms. If you handwrite a Makefile, and it works on your machine, there is a good chance that it won't on mine.
Do you know what unix your users will be using? Or even which distribution of Linux? Do you know where they want software installed? Do you know what tools they have, what architecture they want to compile on, how many CPUs they have, how much RAM and disk might be available to them?
The *nix world is a cross-platform landscape, and your build and install tools need to deal with that.
Mind you, the auto* tools date from an earlier epoch, and there are many valid complaints about them, but the several projects to replace them with more modern alternatives are having trouble developing a lot of momentum.
Lots of things are like that in the *nix world.
Autotools is a disaster.
The generated ./configure script checks for features that have not been present on any Unix system for last 20 years or so. To do this, it spends a huge amount of time.
Running ./configure takes for ages. Although modern server CPUs can have even dozens of cores, and there may be several such CPUs per server, the ./configure is single-threaded. We still have enough years of Moore's law left that the number of CPU cores will go way up as a function of time. So, the time ./configure takes will stay approximately constant whereas parallel build times reduce by a factor of 2 every 2 years due to Moore's law. Or actually, I would say the time ./configure takes might even increase due to increasing software complexity taking advantage of improved hardware.
The mere act of adding just one file to your project requires you to run automake, autoconf and ./configure which will take ages, and then you'll probably find that since some important files have changed, everything will be recompiled. So add just one file, and make -j${CPUCOUNT} recompiles everything.
And about make -j${CPUCOUNT}. The generated build system is a recursive one. Recursive make has for a long amount of time been considered harmful.
Then when you install the software that has been compiled, you'll find that it doesn't work. (Want proof? Clone protobuf repository from Github, check out commit 9f80df026933901883da1d556b38292e14836612, install it to a Debian or Ubuntu system, and hey presto: protoc: error while loading shared libraries: libprotoc.so.15: cannot open shared object file: No such file or directory -- since it's in /usr/local/lib and not /usr/lib; workaround is to do export LD_RUN_PATH=/usr/local/lib before typing make).
The theory is that by using autotools, you could create a software package that can be compiled on Linux, FreeBSD, NetBSD, OpenBSD, DragonflyBSD and other operating systems. The fact? Every non-Linux system to build packages from source has numerous patch files in their repository to work around autotools bugs. Just take a look at e.g. FreeBSD /usr/ports: it's full of patches. So, it would have been as easy to create a small patch for a non-autotools build system on a per project basis than to create a small patch for an autotools build system on a per project basis. Or perhaps even easier, as standard make is much easier to use than autotools.
The fact is, if you create your own build system based on standard make (and make it inclusive and not recursive, following the recommendations of the "Recursive make considered harmful" paper), things work in a much better manner. Also, your build time goes down by an order of magnitude, perhaps even two orders of magnitude if your project is very small project of 10-100 C language files and you have dozens of cores per CPU and multiple CPUs. It's also much easier to interface custom automatic code generation tools with a custom build system based on standard make instead of dealing with the m4 mess of autotools. With standard make, you can at least type a shell command into the Makefile.
So, to answer your question: why use autotools? Answer: there is no reason to do so. Autotools has been obsolete since when commercial Unix has become obsolete. And the advent of multi-core CPUs has made autotools even more obsolete. Why programmers haven't realized that yet, is a mystery. I'll happily use standard make on my build systems, thank you. Yes, it takes some amount of work to generate the dependency files for C language header inclusion, but the amount of work is saved by not having to fight with autotools.
I dont feel I am an expert to answer this but still give you a bit analogy with my experience.
Because upto some extent it is similar to why we should write Embedded Codes in C language(High Level language) rather then writing in Assembly Language.
Both solves the same purpose but latter is more lenghty, tedious ,time consuming and more error prone(unless you know ISA of the processor very well) .
Same is the case with Automake tool and writing your own makefile.
Writing Makefile.am and configure.ac is pretty simple than writing individual project Makefile.