I am a student. I am proficient with C++. I know that C++ and C are very similar and that a C++ compiler can compile C. However I want to become comfortable with C for a multitude of reasons. I was wondering if there is an option I can include with g++/gcc that will throw a error if I use C++.
Thank you
To compile with the c use the -ansi synonymous with the -std=c89 flag.
gcc -ansi
You could put in, say, major includes in your code something like
#ifdef __cplusplus
#error "This is C code, please use C compiler"
#endif
and C++ compiler will throw error on preprocessor stage
I am currently in the process of switching compilers.
From microtech to GNU GCC/G++ coldfire..
I keep receiving the following error and can not find a simple solution:
warning: ANSI C++ forbids declaration `interrupt' with no type
I know the line that it is failing on:
friend interrupt void IrqCtmMCSM2(void);
Could someone offer suggestions please?
Thanks for your time.
Is there any way to convert the llvm IR to c code and keep its semantics?
For example, can we compile the c code first to llvm IR and then compile it back to another piece of c code. I don't expect that these two files will be the same. But they need to have the same functionality.
Thanks
You can use the C backend, with llc -march=c
Before I start building one myself;
Is there a wrapper for C or C++ which does the same thing as SVNKit?
There is an API provided in C - see the Subversion Documentation
i am looking for a way, how i can integrate a c++ code with fortran code (i want simply call some C/C++ functions in the fortran code).
I have found some proposals for gcc or console compilers, but i have not any idea how to translate this approach to solve integrationproblem within the visual studio.
At the time I am thinking about creating a dll form c++ code and calling it from Fortran code.
Has someone already seen a solution? Or what is about overhead for calling function from dll? My fortran code transfers a lot of memory into C function, is there any problems, if i would solve this problem with dll?
thx.
PS
I am using Visual Studio 2008 Prof and Intel compilers 10
PPS
I think, i have to specify more concrete, what i want: i want to compile a fortran project in visual studio, which uses some C functions.
There is a new way to do this that has many advantages -- use the Fortran 2003 ISO C Binding. This is a standard and therefore largely OS and language independent way of interfacing Fortran and C (and any language that will use C calling conventions). Intel Fortran 11 supports along with numerous other compilers -- not sure about version 10. Using the ISO C Binding, you can match any C name (any case), don't have to worry about underscores (and variations between compilers) and can specify the types and calling methods (by reference, by value) for the arguments. Intel provides some examples in a folder with their compiler; there are also examples in the gfortran manual and a discussion of additional considerations for Windows. There are previous questions & answers here and on the Intel Fortran forum.
I integrated C and Fortran about 20 years ago and maintained this integration up to 5 years ago. The tricks I used were:
I noticed that the Fortran compiler puts all symbols in uppercase, so make sure your C/C++ functions are written in uppercase as well. To verify how symbols are put in the .OBJ file, use DUMPBIN.
The Fortran compiler does not understand the name-mangling done by the C++ compiler. Compile all your C++ functions using the C style convention (using extern "C")
Arguments in Fortran are always put on the stack using references/pointers. Therefore, use pointer-arguments in your C function.
To be honest, I gave up integrating C and Fortran when I switched to VS2005, so things might have changed since then. Nevertheless, it's still a good idea to use DUMPBIN to see what kind of symbols the Fortran compiler produces, and adjust the compilation of C/C++ sources to fit with that.
We do it where I work.
Assuming you are using the Intel Fortran compiler, look up its docs. By default Intel Fortran passes everything by reference and (I believe) uses the C calling convention, with an all caps identifier. Strings are a particular issue, as Fortran likes to pass the length as a hidden parameter, with a compiler setting for where it goes in the parameter list.
A wise programer doesn't rely on defaults (where a mistake can lead to undefined behavior), and will use the intel INTERFACE statements to specify calling convention, parameter passing, and the link name for the routine. The information on this page (ATTRIBUTES Properties and Calling Conventions) is a must-read. In particular you need it to understand the arcane rules for when and where string length parameters will be passed. I have a printout of it that I keep on my person. :-)
One other thing to note is that versions of VisualStudio past 6 don't like mixed Fortran and C projects. We solved the problem by creating custom project files calling out to makefile, but that's a PITA. I'd suggest going with the flow and using separate projects unless you are doing this a lot like we are.
Solution found:
solution link
i have had several problem with linking, which could be solved with adding in project properties.
code for testing:
#include <stdio.h>
extern "C"
{
void f()
{
printf("hi from c\n mega test");
}
}
fortran code
PROGRAM HelloWorld
use, intrinsic :: iso_c_binding
implicit none
interface
subroutine f( ) bind( c )
use, intrinsic :: iso_c_binding
end subroutine f
end interface
call f
END PROGRAM HelloWorld
on demand i can upload the testproject. thanks all, hopefully it was my last problem with c and fortran
I was able to build obj from fortran sources thanks to the Custom Build Tools of Visual Express 2010. I guess it is also possible in Visual Studio.
If you want to mix C and Fortran together, there is a good tutorial here. It was written for gcc compilers but you should be able to learn how to deal with name mangling easily.
Depending on the compiler, compiled subroutines/functions are Uppercase/lowercase, with a trailing underscore, with a leading underscore,... For a succesfull linkage, you could use dumpbin tools to see how the name appears in the objectfile.
An other way is to use iso_c_binding modules, but it is available with Fortran 2003 only.
This is the how it works with gcc and console
c.c:
#include <stdio.h>
void f_()
{
printf("Hi from C\n");
}
fortran.f90
PROGRAM HelloWorld
CALL f
END PROGRAM HelloWorld
Makefile
SRCDIR=.
all: clean release run
release:
gcc -c c.c -o c.out
gfortran -c fortran.f90 -o fortran.out
gfortran -o out.exe fortran.out c.out
run:
out.exe
clean:
#$(ZSHMAGIC) rm -rf *.exe core* *.o a.out 2> /dev/null
One other question: have i always add '_' after c-function name, which i use in the fortran program?