In this documentation HP Fortran doc, the OPEN statement accept SHARED and READONLY options.
In this documentation Standard Fortran 2008 doc, the OPEN statement dosn't accept SHARED or READONLY options.
Since I'm using gfortran comes with gcc 4.4.7 to compile a Fortran source file on Linux,I used a ruse to get around half the problem. I used
OPEN(...,ACTION=READ,...) instead of READONLY.
But can't find an other ruse (:)) to replace SHARED Option. (Like Something=Shared).
Anyone have a ruse to get arround that?
Those IO extensions (SHARED, READONLY, etc) as well as other extensions, as would be available with DEC based Fortran should be available in GCC/gFortran via the "-fdec" and related compiler switches.
However, I found some confusion in the online GCC docs. Apparently, some older versions of gFortran (and in particular g77) may require the compiler to have been built with the libf2c element, and there may be differences on Unix (c.f. Win etc).
It is not clear exactly which versions of gFortran accept this. For example, under Windows, with GCC/gFortran 6.x, it would not recognise the "-fdec" switch.
Apparently, GCC/gFortran v7.x have all that working, but v7 is still in "development mode" ... are you feeling lucky :-) ?
Also, some references give dire warnings about reliance on "extensions".
Here are some pages of interest:
https://gcc.gnu.org/wiki/GFortran/News
https://gcc.gnu.org/onlinedocs/gfortran/Extended-I_002fO-specifiers.html
https://gcc.gnu.org/onlinedocs/gfortran/Option-Summary.html
https://gcc.gnu.org/onlinedocs/gfortran/Fortran-Dialect-Options.html
The last link seems particularly "dire" on the subject.
Related
I am studying a algorithm code which uses some c++11 features, however my linux system only has the gcc4.4.7 and I donot have permission to update this version. I was told that by running some kind of scripts can solve this problem, that means using gcc4.4.7 can still compile the c++ code which has the c++11 features.
my problem is that currently I only have gcc4.4.7 in linux system, so I wander if there is a solution that can help me compile a algorithm code which uses the c++11 features like the keyword "nullptr","constexpr" and so on, just using gcc4.4.7.
By the way,I have already know that gcc4.7 and above can support c++11.
Thank you very much!
If the compiler doesn't support a language feature, there is no magic "script" to run to alter the compiler's understanding of the code. As seen here some core C++11 features are not available in gcc 4.4.
So what can you do?
Ask your sysadmin to give you temporary permission to install, or ask him to install it.
You could install the latest gcc locally on your account. This needs less permissions than the classical install.
Alternately, you can install gcc from source in a local directory. This should be 100% doable without any special permission (other than write on your home dir)
Alternately, if the algorithm you are studying doesn't have many sources and doesn't use any library other than boost, you can compile and run it online. You can search for yourself, there are many C++ online compilers. http://melpon.org/wandbox/ is great because it supports multiple source files, the boost libraries and even development versions of future versions of gcc and clang.
I was wondering which compiler is better to use on Windows OS (8.1) in temrs of compatibility to c++11's (and later 14) functions, liberies and features (like lambdas) and is also comfortable to use (less bugs).
I am a university student hence I'm not looking at the subject product-wise (even though I do like to code a bit more than just projects for my studies).
I am currently using eclipse luna IDE if it matters.
Notice that compiler != IDE.
VC++ is one of the most populars on Windows and depending on its version it has a good support for C++11 features. Check the list on the msdn blog to find out if there's everything you need.
Gcc is also ported to Windows and you can install MinGW to use it (4.8.1.4 at the moment of writing this). It is pretty complete on C++11.
Clang is also available for the Windows platform and it is also complete on C++11 support (plus it has good diagnostic messages), but notice that you will have to use another linker since clang doesn't ship with one (although there is an ongoing effort to write it: http://lld.llvm.org/)
All the compilers I cited above are pretty stable but, based on my experience, if you're looking for latest and greatest C++11/14/17 features, you might just want to go for gcc or clang (VC++ is slower in adding support for newest features and the compiler is undergoing a huge update to modernize). Just keep in mind that these are compilers and not just IDEs, an IDE is a front-end supporting program that uses a compiler undercover to compile files.
To set up a C++11 compiler, I suggest installing MSYS2, it has a package manager (pacman) that can install fresh versions of GCC, GDB, Clang and many libraries like SDL, Lua etc. Very easy to use too.
As far as GCC vs CLang goes - I really tried hard to make CLang work (which is presumably faster and more friendly than GCC - produces better warnings, etc.), but failed. Issues were that CLang (which comes with MSYS2) is hard-coded to use GCC linker which produces some strange linker errors when using libstdc++ (std implementation from GCC). libc++ (a new implementation designed to work with CLang) didn't worked for me on Windows either.
So you either try build CLang from sources and hope that some configuration will work with C++11 library, OR just stick with GCC which works just fine out of the box.
As IDE, I suggest to take a look at CLion. It is very comfortable (infinitely more user-friendly and intuitive than Visual Studio, IMO). Just install it and point it to the mingw64 (or mingw32) folder of MSYS2, it will auto-detect everything for you.
It only works with CMake projects though.
If I build a DLL with Rust language, does it require libgcc*.dll to be present on run time?
On one hand:
I've seen a post somewhere on the Internet, claiming that yes it does;
rustc.exe has libgcc_s_dw2-1.dll in its directory, and cargo.exe won't run without the dll when downloaded from the http://crates.io website;
On the other hand:
I've seen articles about building toy OS kernels in Rust, so they most certainly don't require libgcc dynamic library to be present.
So, I'm confused. What's the definite answer?
Rust provides two main toolchains for Windows: x86_64-pc-windows-gnu and x86_64-pc-windows-msvc.
The -gnu toolchain includes an msys environment and uses GCC's ld.exe to link object files. This toolchain requires libgcc*.dll to be present at runtime. The main advantage of this toolchain is that it allows you to link against other msys provided libraries which can make it easier to link with certain C\C++ libraries that are difficult to under the normal Windows environment.
The -msvc toolchain uses the standard, native Windows development tools (either a Windows SDK install or a Visual Studio install). This toolchain does not use libgcc*.dll at either compile or runtime. Since this toolchain uses the normal windows linker, you are free to link against any normal Windows native libraries.
If you need to target 32-bit Windows, i686- variants of both of these toolchains are available.
NOTE: below answer summarizes situation as of Sep'2014; I'm not aware if it's still current, or if things have changed to better or worse since then. But I strongly suspect things have changed, given that 2 years have already passed since then. It would be cool if somebody tried to ask steveklabnik about it again, then update below info, or write a new, fresher answer!
Quick & raw transcript of a Rust IRC chat with steveklabnik, who gave me a kind of answer:
Hi; I have a question: if I build a DLL with Rust, does it require libgcc*.dll to be present on run time? (on Windows)
I believe that if you use the standard library, then it does require it;
IIRC we depend on one symbol from it;
but I am unsure.
How can I avoid using the standard library, or those parts of it that do? (and/or do you know which symbol exactly?)
It involves #[no_std] at your crate root; I think the unsafe guide has more.
Running nm -D | grep gcc shows me __gc_personality_v0, and then there is this: What is __gxx_personality_v0 for?,
so it looks like our stack unwinding implementation depends on that.
I seem to recall I've seen some RFCs to the effect of splitting standard library, too; are there parts I can use without pulling libgcc in?
Yes, libcore doesn't require any of that.
You give up libstd.
Also, quoting parts of the unsafe guide:
The core library (libcore) has very few dependencies and is much more portable than the standard library (libstd) itself. Additionally, the core library has most of the necessary functionality for writing idiomatic and effective Rust code. (...)
Further libraries, such as liballoc, add functionality to libcore which make other platform-specific assumptions, but continue to be more portable than the standard library itself.
And fragment of the current docs for unwind module:
Currently Rust uses unwind runtime provided by libgcc.
(The transcript was edited slightly for readability. Still, I'll happily delete this answer if anyone provides something better formatted and more thorough!)
I am a newbie in GCC and Linux. I have been using Visual Studio for almost all course projects, so when switching to GCC and Linux, I feel so suffering, especially when compiling some projects and it complains for some errors.
I think I should do something to get rid of this annoying situation. But I don't know how to get some materials, maybe on linkers, on GCC flags, on libraries, could somebody kind enough pointing out what should I study or pay attention?
Thank you very much
GCC user manual has to be your first reference..and you can get its online/pdf versions here..
There is lots of online documentation for the GNU tools:
Online GCC documentation
Online LD documentation
Online GLIBC documentation
Linux manpages and infopages are one of the most important resources, and one of the most confusing for Windows users (SCNR: because it is fairly good, complete and useful documentation that comes for free and pre-installed on the system). You can reach them via the command-line man and info commands combined with the program, e.g.
man gcc
man fopen
info gcc
Sometimes, you need to install an extra -doc package for the man or the info pages. The gcc manual, for example, is available as an info page.
The second thing you need to learn is to look at the documentation of the right tool. Visual Studio performed the jobs of at least a dozen UNIX programs, so read the motivation section of the documentation and try to understand what program does what job. That is: You usually need an editor (vim), a compiler (gcc), a linker (ld), and archive indexer (ranlib) and a debugger (gdb) in your toolchain under Linux, even though you needn't call all of these by hand.
In addition, you should know about the autotools (autoconf and automake) and libtool because they make your job a lot easier.
I'm not sure to understand what is painful for you. Is it the understanding of Linux system libraries, or is it just that it is painful to develop software on Linux, because you didn't caught how experimented Linux developers work, on a day by day or even minute by minute basis?
Setup: I installed Cygwin with the GNU programming lineup (gcc, g++, make, and gdb) and successfully compiled an ran a program that I was working on. Then I decided to install boost into Cygwin because I will need to use typical boost stuff as my program develops. So, using the Cywing setup.exe, I installed boost. After this, the program that I had just successfully compiled and ran no longer worked. (And recall that it didn't depend upon boost.)
I found out that when boost installed, it also installed a new compiler, g++-4.exe, whereas previously I had been using r++-3.exe. Boost had also symbolically linked g++.exe to the new compiler. After I changed back the symbolic link my old program compiled correctly.
Is there any reason that I should be using g++-4 rather than g++-3?
g++ 3 is very old and the gcc community has long since dropped maintenance of it. (GCC 4.3 is currently the oldest maintained release series.) There have been lots of language conformance improvements in newer versions (both in accepting valid code and rejecting bad code), so you'll have an easier time going forward if you bite the bullet now. You can check the release notes for each series (e.g. for 4.0) for explanations of these improvements and the code changes they might require. Personally, I find programming much more enjoyable when I can reason about programs according to a precise language specification, and only rarely be forced to understand the quirks of a particular compiler.
Also, Boost support for g++ 3 seems to be nearing an end, as Boost 1.44 considers GCC 3(.4.6) as an "additional test compiler" on only a single platform (RHEL). Boost development is linear (not branched), so you can find yourself in a situation where you need to upgrade to get bug fixes, but then find that your platform is no longer supported.