I use Fedora 24. I write Ansi C programs in Vim, using it's native autocompletion under ^N. And everything works fine until I define library in another file like this:
fileA.c
#include <allegro5/allegro.h>
#include "fileB.c"
fileB.c
...
If I try to autocomplete in fileA.c it looks up in both file b and library.
But in file a it searches only in fileA.c. How can I look up for library's functions and constants in fileB.c?
When you are in fileA.c, completions are pulled (among other places) from all includes in that file and includes in those includes, recursively.
This happens because the default value of 'complete' contains i.
When you are in fileB.c, completions can't be pulled from any include because you don't seem to have any but they can still be pulled from the current buffer (. in complete), other buffers (w, b, u), and even tags files (t).
That said, explicitly including a resource is necessary in C if you want to use it so I'm not sure it is wise to expect any resource to be available in your code without proper includes.
Related
I'm trying to include a folder that contains a combination of around 60 .h and .hpp files. This folder contains libraries for programming robots with a Wallaby (a mini-computer-like device) for Botball competition. include is located in the same place as main.c (inside code). Up until now, this is what my header for including libraries looks like:
#include "../code/include/accel.h"
Just like accel.h, I have 60 other .h and .hpp files inside include. So, coming to my question, do I need to type out all the 60 header lines? or is there a way to include the include folder.
I'm using Clion for this project, if I can't include the folder itself, does anyone know of a shortcut in Clion to include all the files in include.
I was also thinking of using some sort of placeholder for the folder name and only specify the file type. So, for example: #include "../code/include/(generic placeholder name).h". I have no clue if something like this exists.
I would also request you to keep in mind that I'm a beginner to programming, so please keep your answers simple.
This is just for some extra info:
The Wallaby is a mini computer to which you would connect your sensors, motors, servos and cameras in order to control a robot for the Botball competition. Usually, one can connect to the Wallaby either via Wifi Direct or a cable and write programs on it directly through an online interface (not entirely sure of the word for it, but you just type in an IP address in your browser and it brings up an interface where you can make projects and code). All the code written in that interface saves directly onto the Wallaby. Here the default include statement is #include <kipr/botball.h>, so I'm assuming that botball.h (which is located on the Wallaby's storage) has all those 60 libraries consolidated in it. I got the include folder that I'm using from GitHub. This link was provided to me by one of the Botball organisers. So the main point in me trying to download the library is so that I can write and successfully compile code even when I'm not connected to the Wallaby. Hope this provides some relevant context.
Thank you for your answers!
What I'd do is
Create (maybe with scripting tools or a specific program) a "all.h" file which includes all the other header files
#ifndef ALL_INCLUDED
#define ALL_INCLUDED
#include "accel.h"
#include "bccel.h"
//...
#include "zccel.h"
#endif
Include "all.h" in your main file
#include "../code/include/all.h"
You can create "all.h" automatically every time you build your code.
CLion is an IDE for Clang and GCC. These compilers are instructed to search paths for include files by specifying -I<path> command line arguments. Any number may be specified, and they are searched in the order given, and the first match found is the file that gets included.
I am not familiar with CLion specifically but no doubt it has a dialog somewhere where you can set header file search paths.
Edit: It seems that CLion may not make this so straightforward. I understand that you have to add then via CMake: https://cmake.org/cmake/help/v3.0/command/include_directories.html#command:include_directories, but after that, the IDE will not recognise the header in the editor and will warn you of unrecognised files and will not provide code comprehension features. I believe it will build nonetheless.
I am currently learning the C programming language and I'm having some issues with importing modules I created.
I created a small module to read with fgets and flush the buffer from stdin perfectly and I don't want to keep writing the code every single time. I just want to import this small module like I used to do in Python. I didn't knew how because I'm not using an IDE. I'm just compiling with gcc in terminal and using a text editor. I tried to search with Google,but in vain.
You should create a header for your module that declares the functions in the module – and any other information that a consumer of the module needs. You might call that header weekly.h, a pun on your name, but you can choose any name you like within reason.
You should create a library (shared or static — that's up to you) that contains the functions (and any global variables, if you're so gauche as to have any) defined by your module. You might call it libweekly.so or libweekly.a — or using the extensions appropriate to your machine (.dylib and .a on macOS, for example). The source files might or might not be weekly.c — if there's more than one function, you'll probably have multiple source files, so they won't all be weekly.c. You should put this code (the header and the source files and their makefile) into a separate source directory.
You should install the header(s) and the library in a well-known location (e.g. $HOME/include for headers and $HOME/lib for the library — or maybe in the corresponding directories under /usr/local), and then ensure that the right options are used when compiling (-I$HOME/include for the headers) or linking (-L$HOME/lib and -lweekly).
Your source code using the module would contain:
#include "weekly.h"
and your code would be available. With shared libraries in $HOME/lib, you would have to ensure that the runtime system knows where to find the library. If you install it in /usr/local, that is done for you already. If you install it in $HOME/lib, you have to investigate things like /etc/ld.so.conf or the LD_LIBRARY_PATH or DYLIB_LIBRARY_PATH environment variables, etc.
You need to create a header file (.h) with your function declarations types and extern variables. Then in the program where you want to use those functions include this .h file and and add the compiled .o file (with your functions) to the object file list. And you are done.
I have some custom .h files placed under /usr/include, but in a directory (/usr/include/itsmag1c), and I'm trying to include them in my C file. I'm guessing that because I use
#include "filename.h";
for files in the same directory, and I would use angle brackets for including a file like math.h or stdio.h. Am I right in guessing that I would use the angle brackets for including my custom header files? If so, my program wont compile, I get the error that the included files cannot be found. Can someone please point to me how I would include these files, or would it be best to have them in the same directory as my program?
Two choices:
Use #include <itsmagic1c/filename.h>
Use #include <filename.h> as before but add a -I switch.
Boost etc use method 1. (which works well provided you have Boost installed in system locations as you would on a reasonably standard Linux box with reasonable package management).
Method 2. is fine too, but more work on the build system, Makefiles, etc.
Usually, you would put your own headers in the same directory or in a subdirectory. Same-dir includes work with "". For bracket includes, if you use gcc, you can pass additional include directories with
-Irelativedir
or
-I/usr/local/yourpath.
How to install new units (i mean includes ex: stdio.h) for my C, and how to download more?
put the header file on the same folder as your main source file,
ex:
/folder /-->main.c
-->function.h
-->function.c
then on main.c include it by writing :
#include "function.h"
the quotes are used to include a header file that's on the same folder as your c source file
u can also write your own and include them like above.
You're looking for libraries. The headers (normally) just contain information to tell the compiler about the content of the library. There are quite a few C libraries to be found, covering all sorts of different topics. Of course, SourceForge isn't the only place to look -- Github and Google code would be a couple more obvious ones.
When Eclipse creates a new file (.c or .h file) in a C project the editor always auto creates a #define at the top of the file like this: If the file is named 'myCFile.c' there will be a #define at the start of the file like this
#ifndef MYCFILE_C_
#define MYCFILE_C_
I have seen other editors do this as well (Codewright and SlikEdit I think).
The #defines don't seem to do anything for the editor as I can just delete them without any problem, and I can't think of a reason why I would want to use them. Does anyone know why they are there?
It's to guard against multiple definitions.
Sometimes people include a whole .c file in other .c files (or even .h files), so it has the exact same purpose of preventing an include file from getting included multiple times and the compiler spitting out multiple definition errors.
It is strange, though, that it would be the default behavior of an editor to put this in anything but a .h file. This would be a rarely needed feature.
A more modern version of this is to use:
#pragma once
It is quite unusual to see this in a .c file, normally it is in the header files only.
I think it's a throwback of C include issues, where multiple copies of the source would get included - unless you are meticulous with include chains (One file includes n others).
Checking if a symbol is defined and including only if the symbol is defined - was a way out of this.