Emacs Auto-include in C - c

When using java and eclipse, there is a button to automatically include whatever standard libraries need to be included. Is there any analogous option for C and emacs to save me the effort of writing out includes from standard library?

Unfortunately, I don't think so. In general a feature like that requires the ability to fully parse C code and the only part of Emacs that can do that is CEDET. CEDET has a lot of infrastructure for adding features, so this would be the place to look.
However, C's lack of namespaces would make building something like that very error prone. Often most includes are application specific anyway, so I can't see something restricted to the stdlib be incredibly useful.
You can save yourself some typing with yas-snippets, but that is still a long way from auto-magically figuring out your includes.

Related

C code preprocessing in Perl

I work on the C code parser in Perl.
At the moment I need to pre-process the code.
Implementation of the pre-processing seems to be a lot of work, so I am looking for a script or library that will allow to pre-process the file.
I found the following possibilities:
Text::CPP
Filter::CPP
Both of these require cpp which I don't have on my Windows machine. Are there any other options?
I'm not sure I understand your needs, but you are right that implementing this yourself is probably a poor choice. I was recently looking for alternative C preprocessors as well.
The Text::CPP module should only require a compiler to compile itself. If you can find a precompiled version, it should work for you.
The JCPP Java C Preprocessor by the same author could probably be made to work. You'd likely have to process externally and then load the result.
Filepp is an older Perl program that claims CPP compatability. There is a precompiled Windows binary to download.
There is a brand new Lua C-Preprocessor LCPP that might be something you could work with. Probably best as a standalone, but you might be able to use Inline::Lua.
SWIG comes with its own preprocessor implementation. I presume this would be available for Windows.
What else? The Boost Wave Preprocessor might work well and is available for Windows.
The MSVC Compiler can preprocess to a file.
Still, the easiest and best long term solution may be to just install CPP. It comes as part of GCC, which you can get from Cygwin or MinGW.

Code refactoring tools for C, usable on GNU/Linux? FOSS preferable

Variations of this question have been asked, but not specific to GNU/Linux and C. I use Komodo Edit as my usual Editor, but I'd actually prefer something that can be used from CLI.
I don't need C++ support; it's fine if the tool can only handle plain C.
I really appreciate any direction, as I was unable to find anything.
I hope I'm not forced to 'roll' something myself.
NOTE: Please refrain from mention vim; I know it exists and what its capabilities are. I purposefully choose to avoid vim, which is why I use Komodo (or nano on the servers).
I don't think that a pure console refactoring tool would be nice to use.
I use Eclipse CDT on linux to write and refactor C-Code.
There exists also Xrefactory for Emacs http://www.xref.sk/xrefactory/main.html
if a non console refactoring tool is o.k for you as well.
C-xrefactory was an open source version of xrefactory, covering C and Java, made available on SourceForge by Marián Vittek under GPLv2.
For those interested, there's an actively maintained c-xrefactory fork on GitHub:
https://github.com/thoni56/c-xrefactory
The goal of the GitHub fork is to refactor c-xrefactory itself, add a test suite, and try to document the original source code (which is rather obscure). Maybe, in the future, also convert it into an LSP C language server and refactoring tool.
C-xrefactory works on Emacs; setup scripts and instructions can be found at the repository. Windows users can run it via WSL/WSL2.
You could consider coding a GCC plugin or a MELT extension (MELT is a domain specific language to extend GCC) for your needs.
However, such approach would take you some time, because you'll need to understand some of GCC internals.
For Windows only, and not FOSS but you said "any direction..."
Our DMS Software Reengineering Toolkit" with its C Front End can apply transformations to C source code. DMS can be configured to carry out custom, complex reliable transformations, although the configuration isn't as easy as typing just a command like "refactor frazzle by doobaz".
One of the principal stumbling blocks is still the preprocessor. DMS can transform code that has preprocessor directives in typical places (around statements, expressions, if/for/while loop heads, declarations, etc.) but other "unstructured conditionals" give it trouble. You can run DMS by expanding the preprocessor directives out of existence, or more imporantly, expanding out the ones that give it trouble, but mostly people don't like this because they prefer to keep thier preprocessor directives. So it isn't perfect.
[Another answer suggested Concinelle, which looks pretty good from my point of view. As far as I know, it doesn't handle preprocessor directives at all; I could be wrong and it might handle some cases as DMS does, but I'm sure it can't handle all the cases].
You don't want to consider rolling your own. Building a transformation/refactoring tool is much harder than you might guess having never tried it. You need full, accurate parsers for the (C) dialect of interest and just that is pretty hard to get right. You need a preprocessor, symbol tables, flow analysis, transformation, code regeneration machinery, ... this stuff takes years of effort to build and get right. Trust me, been there, done that.

Can I use winnt.h in Linux?

My program is written in C. I want to use library winnt.h, but I don't use Windows anymore.
Seems like a strange question; you should probably clarify which function(s) you actually need from winnt.h so that you can learn the Linux equivalent. winnt.h isn't really a general purpose "library", it's just an interface to built in Windows-specific functions.
With that as a major caveat, you may get some degree of what you want by attempting to run your app with the help of Wine. See http://www.winehq.org/ If you're just trying to run an existing app, that's may be a reasonable solution. If you're trying to make a Linux version of your app, though, that won't help you very much.
No, well you could but it's not going to do any good - the.h file just declares functions that are defined in libs that are only on windows
No. You can't.
winnt.h contains lots of macros that depend on a Windows environment and a lot of function declarations that only exist in Windows-specific libraries. So, it's not really useful (or possible) to use winnt.h on Linux.
That said, you can use Winelib, which includes most of the functionality exposed by those Windows-specific headers, and you can get those features by linking your program with Winelib. In general, this is probably not a good idea, because Winelib is relatively unstable (the functionality of a given API function may be absent, incomplete, buggy, or incompatible compared to the native Windows version). It is a much better idea to look for a Linux-native alternative to what you need.
What parts of winnt.h do you want to use? Of course, if you need some nice macroses or type definitions from it, you can freely copy it to your own header file (of course, with dependencies). But if you include all winnt.h file to your program in linux environment, you will get tons of error messages. One of the reasons for it is pronounced by Martin Beckett in his reply.

How can I best check for C library dependencies?

I'm building something that installs a high-level stack, and to do that, I need to install the lower-level stuff.
The simplest way to look for whether, say, Java is installed, is to just shell out a which java in a shell script and check if it can find it. I'm now to the point where I need to do some libraries without an obvious binary- basically stuff that is an include from within C. libxml, for example.
I'm woefully green to C in general, so this makes things a little tricky for me. :) Ideally I could just make a shell script that calls a little C applicaiton that calls #include <xxxx>, where xxxx is the library that I'm checking the existence of. If it can't find it, it errors out. Unfortunately, of course, all that happens prior to compilation, so it's not as dynamic as I'd like.
I'm doing this on a system that probably doesn't have anything installed on it (be it high-level language or package managers or what have you), so I'm looking more for a basic shell script way of doing things (or maybe some clever C or command-line gcc options). Or maybe just manually search the include paths that gcc would look for anyway /usr/local/include, /usr/include, etc.). Any thoughts?
Autotools is really what you need. Its a huge (and bizarre) framework for dealing with this very problem:
http://www.gnu.org/software/autoconf/
You can also use pkg-config, which will work with newer software making use of that mechanism:
http://pkg-config.freedesktop.org/wiki/
this is the purpose of configure (part of automake and autoconf)

Refactoring C/C++ in Vim (e.g. method extraction like in Eclipse)

Are there any plugins or built-in methods in Vim for performing refactoring on C or C++ code, something like the refactoring tools in Eclipse?
I'm especially keen on the extract method refactoring tool from Eclipse that will determine parameters from new methods and typically also guess a variable to use as the return value.
No, although Vim is a good environment for editing, and can be customised in a lot of ways (code folding, syntax colouring, macro expansion etc.) most of these are done on the syntax level, rather than the semantic level. Even the code folding just matches up opposing braces.
To do a proper refactoring, you have to have a lot of semantic knowledge about the AST, what variables are declared in which scope, and so on. IDEs like Eclipse build up a cache of the variables defined in each lexical scope, so that they can quickly refer back to where they are used in terms of determining what to rename and where.
That's not to say that you can't do some things syntactically; after all, one can just take out a block of code and put it into a separate function easily enough. You might even be able to guess at some parameters (e.g. find a list of the variables, find out which ones have local declarations, remove them and what's left are your parameters. But Eclipse also does other things—like figuring out whether any variables are modified in the function, and ensuring they're passed back by the return value. It also checks for any thrown exceptions, and add them to the list.
The net effect is that whilst you may be able to approximate some of these in Vim, you really aren't going to be able to get this working in a Vim-only enviornment. You could either use a Vim-like keybinding in Eclipse proper, or look at eclim. From the home page:
The primary goal of eclim is to bring
Eclipse functionality to the Vim
editor. The initial goal was to
provide Eclipse’s java functionality
in vim, but support for various other
languages (c/c++, php, python, ruby,
css, html, xml, etc.) have been added
and several more are planned.
Eclim is less of an application and
more of an integration of two great
projects. The first, Vim, is arguably
one of the best text editors in
existence. The second, Eclipse,
provides many great tools for
development in various languages. Each
provides many features that can
increase developer productivity, but
both still leave something to be
desired. Vim lacks native Java support
and many of the advanced features
available in Eclipse. Eclipse, on the
other hand, still requires the use of
the mouse for many things, and when
compared to Vim, provides a less than
ideal interface for editing text.
That is where eclim comes into play.
Instead of trying to write an IDE in
Vim or a Vim editor in Eclipse, eclim
provides an Eclipse plug-in that
exposes Eclipse features through a
server interface, and a set of Vim
plug-ins that communicate with Eclipse
over that interface.
This not only gives an Eclipse-like environment, it is Eclipse. But you still get the navigation and text editing features of vim. It sounds like this might suit your needs, although the documentation on refactoring support doesn't indicate that it provides an extract method functionality.
I've written a generic refactoring plugin. C++ is one of the primary languages handled (as it's my primary language at work). Method extraction is supported.
For C++, the plugin is able (thanks to ctags) to deduce most (but unfortunately not always all -- thanks to ctags...) of the variables coming in and out of the extracted function.
I still have to write a little dialog box to select how the in/out variables shall be exchanged (const ref, rvalue ref, copy, pointer, tuples, struct, and so on) (BTW, help is welcome as GUIs are not my thing ^^').
After searching high and low for vim with refactoring for C++, this is the best solution I have come up with.
Visual Studio 2013 and higher - Great IDE for C++ development and debugging, but does not have sufficient refactoring or vim
Install the vsvim plugin - Now, you have all the vim navigation, searching, string replacement, etc. (Some advanced features are not supported)
Install Resharp C++ - Great for refactoring at the cost of speed. It makes it a bit clunky, but if you want to infer auto generate methods/variables, rename local/global/method variables or functions, Search for usages in the solution, and more features, makes it extremely worth it.
This is the best combination I found for C++ development, debugging and refactoring. Makes me at least 3x - 5x faster. Hope it helps you as well.

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