The last time I heavily used C was years ago, and it was strictly done on the Windows platform.
Now, I am taking a class where it is required to develop programs to be ANSI C compliant and the code will be compiled using gcc
we a are required to compile the code using:
gcc -g -ansi -pedantic -Wall
how can I reproduce this on MSVS2010? I don't like Ubuntu.
If you only dislike Ubuntu, there are other options for using GCC. For example, you can look into MinGW, which is a full set up of gcc and all related tools for windows. There are also a few IDEs, like Eclipse and Code::Blocks which I'm pretty sure ship with a C compiler that you can configure however you need. There are also other linux distributions or the option of mac if you'd like to try those out.
(Sorry, don't know anything about MSVC, but GCC is pretty much the standard)
And it still could be useful to use Ubuntu, because I assume your class will later give you an exercise with e.g. Posix system calls to use, and then it is better to use some Linux distribution (if you dislike Ubuntu graphical interface Unity, you can use something else).
Related
I searched a little bit and one google search was enough to discover the differences between the gcc and cc compilers, but I did not find the advantages in using one or another to compile C programs
Which compiler should I use? and why?
The compiler installed as part of X-Code on OS/X is a recent version of clang whose development is sponsored by Apple.
gcc is not provided nor supported by Apple.
Unless you install gcc explicitly from one of its distributions, gcc is an alias for clang on OS/X, just like cc.
The reason for this is to support packages that use gcc explicitly as the C compiler.
On your system, it does not matter which alias you use, the compiler invoked will be clang, which has a high degree of compatibility with gcc extensions but generates different code. Both are very advanced and dependable.
I want to use clang on Windows to compile C code.
I'd like to know if it is in fact a standalone compiler that can do that, or are its aims somewhat different?
I've used it before, but it appears now that is was piggy-backing on top of whatever gcc compilers were lying around (mingw for example).
If I try a fresh binary installation of clang 64-bits (and I hide my mingw/gcc directories), then it can't find stdio.h for Hello World. This is running from directly inside the bin directory (C:\clang\bin). If I unhide mingw, it will compile, but then I get errors like this (one mingw compiler is in c:\win):
c:\win\bin\ld.exe cannot find -lgcc_s
Considering clang is a 438MB installation, you'd think it would have it's own include and library files! I want to use clang in place of gcc.
So, what am I doing wrong? (I've seen a few questions also about the inability to find stdio.h, but they weren't helpful. Surely clang must be able to compile Hello World by itself?!)
You are confusing compiler with linker with standard library.
Clang is a full featured independent compiler. But it does not provides the standard library (the library containing stdio.h). Traditionally, on Unix systems, the operating systems must provide the standard library it uses. But since you are using Windows, it doesn't, and for whatever reason it finds the ones from MingW installed. There are many free implementations of C standard library which are compatible with Clang.
Lastly, ld.exe is the linker, and it also, traditionally, must be provided by the system. There is one linker, lld, that I believe is being developed alongside Clang, but for whatever reason, the packager of the version you downloaded just chose to configure clang to simply call ld.
Clang is a completely separate compiler (written entirely from scratch, using LLVM). You don't need GCC to use Clang, as can be shown in the case of FreeBSD (they completely replaced GCC with Clang/LLVM and don't install GCC in the base anymore for licensing reasons). There are a variety of different C compilers other than GCC, it's just that GCC is the most common.
However, no compiler provides the standard C libraries (GCC provides some weird libraries like the one you're trying to use). C libraries are provided separately, and you need to install C libraries in order to compile any significant C program. The error message saying cannot find -lgcc_s tells me that you're trying to link against some library provided by GCC. In this case, you probably want to install that library by installing GCC (but note that you don't need GCC to use Clang.
It does appear that your version of Clang has been compiled to use GNU's linked ld, not LLVM's linked lld. As such, you'll need GCC's linker (or you can recompile clang to use LLVM's linker, or just compile the object files and use lld separately).
I think you are missing a path variable. After install you must manually add a PATH to the Windows Environment.
I am trying to use SSE4.2 intrinsics with clang/llvm but its not compiling, as I get cannot select intrinsic error from LLVM. On the other hand, the same code compiles flawlessly in gcc. So I thought, maybe I can compile that function with gcc, so as to have an object or library file, and then call that library function in my code, which is compiled by clang/llvm. Would that work?
It's possible to compile an object file with GCC in Linux and convert it to work in Visual Studio. I did this recently running Linux in Virtual Box on Windows converting-c-object-file-from-linux-o-to-windows-obj so this should be possible with Clang on Linux or Windows as well.
So not only can this be done cross compiler it can be done cross platform.
You need to get the calling conventions and the object file format correct (and for C++ the name mangling as well) . With GCC when you compile you can tell it which calling convention/API to use with mabi. Then, if going from Linux to Windows, you need an object file converter to convert from e.g. ELF on Linux to COFF on Windows. Of course, there are cases this probably won't work (e.g. if the module relies on a system call that is only in one platform). See the link above for more details.
For any more-or-less complicated c++ code, e.g., one that compiles to vtable - the answer is a resounding NO. The two are NOT compatible.
To illustrate the above point, try to compile the Crypto++ library with g++ (gains about 40% speedup for AES/GCM) and then link your clang++-compiled code with it.
It may or it may not work. Some elements of the ABI can be expected to be the same. For example, I believe both g++ and clang use the Itanium ABI name mangling scheme. Others elements can not. So it depends on how complex the code you're compiling is.
Also, I would suggest opening an LLVM bug for the intrinsic that could not be selected. Clang and LLVM have a very active community, and it's possible someone will pick the bug up quickly.
I'm an avid Python user and it seems that I require MinGW to be installed on my Windows machine to compile some libraries. I'm a little confused about MinGW and GCC. Here's my question (from a real dummy point of view):
So Python is language which both interpreted and compiled. There are Linux and Windows implementations of Python which one simply installs and used the binary to a execute his code. They come bundled with a bunch of built-in libraries that you can use. It's the same with Ruby from what I've read.
Now, I've done a tiny bit a of C and I know that one has a to compile it. It has its built-in libraries which seem to be called header files which you can use. Now, back in the school day's, C, was writing code in a vi-like IDE called Turbo-C and then hitting F9 to compile it. That's pretty much where my C education ends.
What is MinGW and what is GCC? I've been mainly working on Windows systems and have even recently begun using Cygwin. Aren't they the same?
A simple explanation hitting these areas would be helpful.
(My apologies if this post sounds silly/stupid. I thought I'd ask here. Ignoring these core bits never made anyone a better programmer.)
Thanks everyone.
MinGW is a complete GCC toolchain (including half a dozen frontends, such as C, C++, Ada, Go, and whatnot) for the Windows platform which compiles for and links to the Windows OS component C Runtime Library in msvcrt.dll. Rather it tries to be minimal (hence the name).
This means, unlike Cygwin, MinGW does not attempt to offer a complete POSIX layer on top of Windows, but on the other hand it does not require you to link with a special compatibility library.
It therefore also does not have any GPL-license implications for the programs you write (notable exception: profiling libraries, but you will not normally distribute those so that does not matter).
The newer MinGW-w64 comes with a roughly 99% complete Windows API binding (excluding ATL and such) including x64 support and experimental ARM implementations. You may occasionally find some exotic constant undefined, but for what 99% of the people use 99% of the time, it just works perfectly well.
You can also use the bigger part of what's in POSIX, as long as it is implemented in some form under Windows. The one major POSIX thing that does not work with MinGW is fork, simply because there is no such thing under Windows (Cygwin goes through a lot of pain to implement it).
There are a few other minor things, but all in all, most things kind of work anyway.
So, in a very very simplified sentence: MinGW(-w64) is a "no-frills compiler thingie" that lets you write native binary executables for Windows, not only in C and C++, but also other languages.
To compile C program you need a C implementation for your specific computer.
C implementations consist, basically, of a compiler (its preprocesser and headers) and a library (the ready-made executable code).
On a computer with Windows installed, the library that contains most ready-made executable code is not compatible with gcc compiler ... so to use this compiler in Windows you need a different library: that's where MinGW enters. MinGW provides, among other things, the library(ies) needed for making a C implementation together with gcc.
The Windows library and MSVC together make a different implementation.
MinGW is a suite of development tools that contains GCC (among others), and GCC is a C compiler within that suite.
MinGW is an implementation of most of the GNU building utilities, like gcc and make on windows, while gcc is only the compiler. Cygwin is a lot bigger and sophisticated package, wich installs a lot more than MinGW.
The only reason for existence of MinGW is to provide linux-like environment for developers not capable of using native windows tools. It is inferior in almost every respect to Microsoft tooolchains on Win32/Win64 platforms, BUT it provides environment where linux developer does not have to learn anything new AND he/she can compile linux code almost without modifications. It is a questionable approach , but many people find that convenience more important than other aspects of the development .
It has nothing to do with C or C++ as was indicated in earlier answers, it has everything to do with the environment developer wants. Argument about GNU toolchains on windows and its nessessety, is just that - an argument
GCC - unix/linux compiler,
MinGW - approximation of GCC on Windows environment,
Microsoft compiler and Intel compiler - more of the same as names suggest(both produce much , much better programs on Windows then MinGW, btw)
I wanted to know what is the current standard C compiler being used by companies. I know of the following compilers and don't understand which one to use for learning purposes.
Turbo C
Borland C
GCC
DJGPP
I am learning C right now and referring to the K&R book.
Can anyone please guide me to which compiler to use?
GCC would be the standard, best supported and fastest open source compiler used by most (sane) people.
GCC is going to have the best support of the choices you've listed for the simple reason that it comes standard in GNU and is the target of Linux. It's very unlikely any organization would use the other three beyond possibly supporting some horrible legacy application.
Other C compilers you might look into include:
Clang: an up-and-comer, particularly for BSD and Mac OS X
Visual Studio Express: for Windows programming
Intel Compiler Suite: very high performance; costs money
Portland Group: another high-performance commercial compiler; used typically for supercomputers
PathScale: yet another commercial high-performance compiler
If you are starting to learn the language, Clang's much better diagnostics will help you.
To make your (job) applications tools section look better, GCC (and maybe Visual Studio) are good to have knowledge of.
GCC (which I use in those rare moments when I use C) or ICC (Intel C Compiler), though ICC is known for making code that runs slowly on AMD processors.
Depends on the platform you are using and planning to learn on or will do future development.
On Windows you can use Visual Studio Express C++ which supports standard ANSI C usage. Option two is Cygwin which is a library and tool set that replicates much of what you would use on Linux or other Unix style OS's ( it uses GCC ).
On the Mac you would want XCode which is the standard development tools including C compiler ( based on GCC ).
On many Unix type systems it will be cc or gcc depending on the OS vendor.
If you have the money some of the paid compilers like the Intel one are exceptional but likely won't be much help in learning the programming craft at this point.
If you use LINUX operating system GCC is the best compiler. You can separate each compiler steps like preprocessing , assembler , linker separately in GCC compiler using some command line options. You can analyze step by step of compilation of your C source code easily. I suggest to go for "GNU C COMPILER(GCC)". You can use "CC" command, its nothing but a symbolic link to GCC.
I can recommend OpenWatcom which was once used to develop Netware. Only supports IA-32 but does it well. Contains a basic IDE and a basic but competent profiler. Something for the real programmer :)
Then there is Pelles C which supports x86-64. It has a basic VC-like IDE but few support programs.
I like these two because the compilers are competent and you get going quickly without having to pore over manuals and wondering what the options mean.
If you are on windows use MinGW or like most have suggested ggo with GCC on Linux
Though ofcourse since it's commandline so you might find Dev-C++ and/or Code::Blocks, Eclipse CDT etc which are IDEs useful for you to make your job simpler.
There is no standard and each compiler and it's libraries differ from one another.
gcc is best and free. GO FOR GNU!