Can we get C/C++ struct's member number, type, name, and format string?

[Jonathan Wakely]

On 19 January 2017 at 02:19, hank fu <hankfumail@gmail.com> wrote:
> Can we get C/C++ struct's member number, type, name, and format string?
>
> Here is one example.
> struct c_test_struct_type {
> int i_var;
> unsigned int ui_var;
> long l_var;
> unsigned long ul_var;
> }
> Is there one an operator provided by GCC to determine the member
> nubmer of this struct? For example, I hope to get 4 by calling
> '__struct_member_number__(struct c_test_struct_type)' .
> Is there one an operator provided by GCC to get the member name of
> this struct? For example, I hope to get string 'i_var' by calling
> '__struct_member_name__(struct c_test_struct_type, 0)'.
> Is there one an operator provided by GCC to get the member type of
> this struct? For example, I hope to get string 'int' by calling
> '__struct_member_type__(struct c_test_struct_type, 0)'.
> Is there one an operator provided by GCC to get the formatted string
> of this struct? For example, I hope to get string "i_var： %d, ui_var：
> %u, l_var： %ld, llvar： %lld" by calling
> '__struct_member_print_format__(struct c_test_struct_type, 0)'.
>
> We can simplify the development if we have such operator. I cannot
> find them in GCC documents.

No, C and C++ do not support reflection.

There are some proposals to add reflection to C++ at some point in the
future, but it will be a long time before GCC supports it.