Forward declare entities in C standard library?

Content Index :

Forward declare entities in C standard library?
Forward declare a standard container?
Will the standard library of C++11 have forward declaration headers?
Legal to forward declare C standard library entities but not C++ standard library entities?
Should one forward declare classes from a namespaced library?
Forward-declare struct which only has definition in a library cpp

Forward declare entities in C standard library?

Tag : c , By : ck1

Date : November 23 2020, 01:01 AM

This might help you Forward declarations of structs are always permissible in C. However, not very many types can be used this way. For example, you can't use a forward declaration for FILE simply because the tag name of the struct is not specified (and theoretically, it may not be a struct at all).
Section 7.1.4 paragraph 2 of n1570 gives you permission to do the same with functions:

void *malloc(size_t);
void abort(void);

/* my code here */

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Forward declare entities in C standard library , Legal to forward declare C standard library entities but not C++ standard library entities , Forward declare a standard container , Forward-declare struct which only has definition in a library cpp , standard c library ,

Forward declare a standard container?

Tag : cpp , By : dexteryy

Date : March 29 2020, 07:55 AM

it fixes the issue Declaring vector in the std namespace is undefined behavior. So, your code might work, but it also might not, and the compiler is under no obligation to tell you when your attempt won't work. That's a gamble, and I don't know that avoiding the inclusion of a standard C++ header is worth that.
See the following comp.std.c++.moderated discussion:

Will the standard library of C++11 have forward declaration headers?

Tag : cpp , By : ap.

Date : March 29 2020, 07:55 AM

I wish this helpful for you No, there are no new forward files, just the old .
The complete I/O-system is large compared to a vector, so the advantage would perhaps not be that significant.

Legal to forward declare C standard library entities but not C++ standard library entities?

Tag : cpp , By : scotta01

Date : November 23 2020, 01:01 AM

I wish this help you The problem is that C++ and C are not compatible at the object level... For example it's different to write:

double atof(const char *);

extern "C" {
    double atof(const char *);
}

Should one forward declare classes from a namespaced library?

Tag : cpp , By : Munir

Date : March 29 2020, 07:55 AM

Hope that helps As @molbdnilo pointed out, there is nothing wrong with forward declaring with namespace. First option is not an option at all, for various reasons I dont want to include header until I have to, forward declaration is always preferred way. Why dont you just provide a header with forward declarations as many boost implementations do? for example boost spirit numerics_fwd.hpp?
Ah, missed @DevSolar comment. IMHO this is the best solution.