I'm writing a GUI to an application, but the main developer wants to set in Makefile if the GUI get or not compiled with the rest. I'm putting all the GTK+ code in a separated file, but in the main file I need to test if the application is being compiled with the GUI or not, so how I can test this?
E.g:
if(COMPILED_WITH_GTK)
#include "my_gtk_stuffs.h"
Assuming that COMPILED_WITH_GTK is an argument to the compiler command in the Makefile (in the form of -DCOMPILED_WITH_GTK) you use a preprocessor directive.
#ifdef COMPILED_WITH_GTK
#include "my_gtk_stuffs.h"
#endif
This tells the preprocessor to only process the #include statement if COMPILED_WITH_GTK is defined.
Have a look here, as well.
Related
I'm trying to set up clang-tidy for enforcing naming conventions in a C project. This project is composed of multiple external sources and uses a plain makefile environment, thus no tool like cmake or bear is available to generate a compilation database.
This is also what I want: Using the custom environment I'd like to selectively invoke clang-tidy for each file that should be checked.
I was configuring the tool, mainly for the check readability-identifier-naming. For testing I have a .c and .h file, both in the same directory, with the following content:
dummy.c
#include "dummy.h"
#include "MISSING_module.h"
// EOF
dummy.h
#ifndef _DUMMY_H_
#define _DUMMY_H_
#include <stdlib.h>
// EOF
The command I'm invoking is
clang-tidy dummy.c -checks='-*,readability-identifier-naming' -- -DCMAKE_EXPORT_COMPILE_COMMANDS=ON`
However, clang-tidy is still following the #include within the C-file and checks for existing headers:
dummy.h:4:10: error: 'stdlib.h' file not found [clang-diagnostic-error]
#include <stdlib.h>
^
Found compiler error(s).
Is there any way to disable this? clang-diagnostic-error is not even enabled as check. Or are there alternative tools I should know of to enforce naming conventions?
Look at the way you are using clang-tidy: the -- option is used to specify compilation options.
clang-diagnostic-error doesn't have anything to do with clang-tidy itself. Those are compiler warnings and you cannot turn them off. Clang-tidy needs the analyzed file to be compile-able to build an AST which it uses internally for the checks. You'll find more on clang-diagnostic-error in clang-tidy documentation.
I am currently trying to create an application in C as an assignment for school, and my professor requires me to use the following to make it compatible with his compiler:
#pragma warning(disable: 4996)
#include<string>
#include<stdlib.h>
#include<time.h>
(I am using visual studio)
And for some reason #include <string> throws up a bunch of run time errors mainly consisting of the one in the title of the question. It pops up within a bunch of other dependencies ranging from cmath, cstudio, cstdlib, cstring, etc. So the bottom line is, can anyone tell me how to fix it? Thanks!
In visual studio you can get this error if you extension is '.c' VS studio will assume the file is type c and not c++ and use the c compiler and not the c++.
In the project settings under advanced options you can select compile as C++ and then files will all be compiled as C++. If you scroll down you will find the flag '-x' on the command line as added to it.
If you are using the gcc compiler this is the same as adding the following to the compiler command '-x c++'
Check the gcc reference for this flag.
The #include <string> is a C++ header file and therefore incompatible with C.
As others have suggested, you can change this to #include <string.h> so that you have a valid C header, however if your professor dictated that you use that specific set of headers, then you need to change your source file to a .ccp file instead of a .c file.
You're including C++ header file. Use #include <string.h>
You are including a C++ library in C code. The header files without any extension are C++ header files. Having ".h" extension are C header files. C++ also accepts C header files still they have no extension. They have given same names having "c" prefix and no ".h" extension.
for example
<string>
is a C++ header
<string.h>
is a C header
<cstring>
is a C header but in a C++ code.
I have a newbie question about the C programming language. I have looked around to find the answer in similar questions but I failed to figure it out.
Assume a simple project consisting of two dirs: src and test. The source and header files are defined by src/main.c, test/foo.h and test/foo.c.
src/main.c:
#include "../test/foo.h"
int main (void) {
int a = VAR; /* works, recognizes declared macro */
some_function(a); /* doesn't work, "undefined reference" */
}
test/foo.h:
#ifndef FOO_H
#define FOO_H
void some_function(int a);
#define VAR 2;
#endif
test/foo.c (redundant but to be complete):
#include "foo.h"
#include <stdlib.h>
void some_function(int a) {
printf("%d", ++a);
}
I created the project in Eclipse and I also compile with it, I figured it wasn't a linking error since the macro gets recognized but the method is not callable.
The reason why I'm using different directories is because I have a lot of files and would like my test code to be separate from my main source code. Note that src and test have the same parent directory.
Any ideas what's going on here? Am I missing something very obvious?
Any help would be much appreciated, thanks in advance!
edit: I'm working on a (Debian) Linux machine and Eclipse uses the gcc compiler.
edit2: Thanks to H2CO3's answer I learned it is indeed a linking error. Since compiling and linking manually every time is quite an overhead, I was wondering if anyone knows how to teach Eclipse to link executables from different directories?
--------------------- SOLUTION ---------------------
edit3: Lol the solution was very easy after all, all I had to do was create a "new source folder" rather than a "new folder". I feel stupid but thanks to you all for replying, H2CO3 in particular!
I figured it wasn't a linking error since the macro gets recognized but the method is not callable.
Non sequitur. Macros are expanded in the preprocessing phase. (And as such, they have nothing to do with linkage at all.) You do have a linker error.
What you have to do is compile both files then link them together, so something like this should work:
gcc -Wall -o dir_one/foo.o dir_one/foo.c
gcc -Wall -o dir_two/bar.o dir_two/bar.c
gcc -o my_program dir_one/foo.o dir_two/bar.o
Also, read this SO question/answer and/or this article to understand how the steps of the compilation process work together. (These are almost the same for C and C++, it's only the name mangling that usually differs.)
I have a C project I'm importing to eclipse to work with. It was prewritten but not a C program, so I imported it as a C Makefile program. Actually for some reason the program was written with shell scripts which called the make in the appropriate directories, I added a Makefile that called the shell script, though I'll probably change it to use only make files.
Anyways the unusual thing is that I get exceptions on all the #define variables used in my C code. The variables are defined in a .h file which is included on the top of the C code, and the #include doesn't haev a warning. I can compile the code and run it without exception. Yet I still get dozens of errors where the #define values are used in the editor. The .h which defines the variables is in a different folder then the C code that throws the excception, but adding the folder with the .h into the C include path didn't do any good. Anyone know how I can get the editor to play nice with my #define variables?
Are you actually typing #DEFINE? It's supposed to be #define. C is case sensitive.
Here are some options to investigate the issue further:
Right-click your project in Eclipse, go to Properties -> C/C++ General -> Paths and Symbols -> Symbols. You can check the symbols defined there, maybe something is messing up the preprocessor there.
Add to your g++ command line the following option: -save-temps. This will output some intermediate compilation files. Check the .i or .ii files - these contain the preprocessed output. More information on this g++ option is here.
Also, it would be nice if you could give some more information about the actual errors/warnings.
How is the .h file included in the .c file?
#include <file.h>
or
#include "file.h"
These have different meanings in the preprocessor.
What is the error that you are getting? Is the .h file not found, causing the other errors?
I really have no idea why this is happening...
I created a win32 application in emacs, and whenever I make it and run it (not through the command prompt), a command prompt window pops up under the window. If I build a win32 application in Code::Blocks, and just run its default template, then it runs without a command prompt window. I looked all through the code of both and can't figure out what might cause this...
I thought it was because I included some printf() statements in there, but I didn't want them to stay there (they were for debugging), so I wrote a macro:
#define DEBUG
in main.c, and
#ifdef DEBUG
#include<stdio.h>
#define DBG printf
#else
#define DBG
#endif
in a header (included after the #define DEBUG of course).
When I undef'd DEBUG, the window still showed up... I don't know what I am doing to make it happen, what sorts of things cause a command prompt window to show up in a win32 application? I tried using all the ****Ex() windows functions instead of just CreateWindow(), etc, but that didn't change anything. I checked and re-checked the class definition and registration, to no avail, and made sure I didn't forget a printf() statement (which would have caused an error even if I did, since stdio.h isn't included unless DEBUG is defined).
This is what I included:
#include<windows.h>
#include<windowsx.h>
#include"main.h"
#include"windowproc.h"
anyone know what can cause this? I even commented out all of my stdio, DBG, printf junk, and it still showed up, and I swear there's no difference between my code and the Code::Blocks generated code, aside from my use of HANDLE_MSG and a few extra functions to split up the code.
Update
I am using MinGW 3.4.5.
using the -mwindows switch worked, thanks
Try linking with the -mwindows switch.
Your program should also have the main method read like so:
int WINAPI WinMain(
....
)
as opposed to the traditional int main().
Related threads:
Why does my QT4.5 app open a console window under Windows?
GCC / C how to hide console window?
Windows makes a difference between "console" and "Windows" applications. Console applications will always be run with an associated terminal.
See this question for details on the differences.
Don't know what compiler you are using but I know GCC needs the -mwindows option to suppress the command line window.