在Visual Studio 2010中从Fortran调用C ++函数 [英] Calling C++ function from Fortran in Visual Studio 2010
问题描述
我想从Fortran调用C ++函数.为此,我在Visual Studio 2010中创建一个FORTRAN项目.此后,我向该FORTRAN项目中添加了一个Cpp项目.当我要构建程序时,会发生以下错误:
Error 1: unresolved external symbol print_C referenced in function MAIN_main.obj
Error 2: 1 unresolved externals
以下是Fortran程序和C ++函数.
Fortran程序:
program main
use iso_c_binding, only : C_CHAR, C_NULL_CHAR
implicit none
interface
subroutine print_c ( string ) bind ( C, name = "print_C" )
use iso_c_binding, only : C_CHAR
character ( kind = C_CHAR ) :: string ( * )
end subroutine print_c
end interface
call print_C ( C_CHAR_"Hello World!" // C_NULL_CHAR )
end
C ++函数:
# include <stdlib.h>
# include <stdio.h>
void print_C ( char *text )
{
printf ( "%s\n", text );
return;
}
非常感谢.
您的问题是,由于使用C ++编译器进行编译,因此print_C
不是C函数,而是C ++函数.由于Fortran代码尝试调用C函数,因此找不到C ++函数.
因此,解决您的问题的方法是
- 可以使用C编译器进行编译,因此您可以获得实际的C代码,
- 或告诉C ++编译器您实际上要声明C函数.
后者是通过extern "C"
完成的,如下所示:
extern "C" void print_C(char *text)
{
printf("%s\n", text);
}
如果您希望能够同时将代码编译为C和C ++,则可以使用
#ifdef __cplusplus
extern "C"
#endif
void print_C(char *text)
{
printf("%s\n", text);
}
符号__cplusplus
是为C ++定义的,但没有为C定义的,因此您的代码将在两者中都可以工作(当然,只要其余代码也保留在该子集中).
I want to call a C++ function from Fortran. To do that, I make a FORTRAN project in Visual Studio 2010. After that I add a Cpp project to that FORTRAN project. The following errors occur when I want to build the program:
Error 1: unresolved external symbol print_C referenced in function MAIN_main.obj
Error 2: 1 unresolved externals
Following are the Fortran program and C++ function.
Fortran program:
program main
use iso_c_binding, only : C_CHAR, C_NULL_CHAR
implicit none
interface
subroutine print_c ( string ) bind ( C, name = "print_C" )
use iso_c_binding, only : C_CHAR
character ( kind = C_CHAR ) :: string ( * )
end subroutine print_c
end interface
call print_C ( C_CHAR_"Hello World!" // C_NULL_CHAR )
end
C++ function:
# include <stdlib.h>
# include <stdio.h>
void print_C ( char *text )
{
printf ( "%s\n", text );
return;
}
Thanks a lot in advance.
Your problem is that since you compile with a C++ compiler, print_C
is not a C function, but a C++ function. Since the Fortran code tries to call a C function, it cannot find the C++ function.
The solution to your problem therefore is
- either compile with a C compiler, so you get actual C code,
- or tell the C++ compiler that you actually want to declare a C function.
The latter is done with extern "C"
, like this:
extern "C" void print_C(char *text)
{
printf("%s\n", text);
}
If you want to be able to compile your code both as C and as C++, you can use
#ifdef __cplusplus
extern "C"
#endif
void print_C(char *text)
{
printf("%s\n", text);
}
The symbol __cplusplus
is defined for C++, but not for C, so your code will work in both (of course only as long as the rest of your code also remains in that subset).
这篇关于在Visual Studio 2010中从Fortran调用C ++函数的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持IT屋!