Are there any possible API like field_count() or is it only possible to get that via macros? There is no such built-in API that would allow you to get this information at runtime. Rust does not have runtime reflection (see this question for more information). But it is indeed possible via proc-macros! Note: proc-macros are … Read more
No, you can’t. Bit field can only be used with integral type variables. C11-ยง6.7.2.1/5 A bit-field shall have a type that is a qualified or unqualified version of _Bool, signed int, unsigned int, or some other implementation-defined type. Alternatively you can do this struct st { unsigned int i: 4; } arr_st[5]; but its size … Read more
You can, but you have to declare it static and const: struct Timer { static const auto start = 0; }; A working example in Coliru. With this limitation, you therefore cannot have start as a non-static member, and cannot have different values in different objects. If you want different types of start for different … Read more
#include <stdio.h> typedef struct { char* c; char b; } a; int main() { printf(“sizeof(a) == %d”, sizeof(a)); } I get “sizeof(a) == 8”, on a 32-bit machine. The total size of the structure will depend on the packing: In my case, the default packing is 4, so ‘c’ takes 4 bytes, ‘b’ takes one … Read more
Right, there’s a number of things to consider. First up: let’s start with the obvious syntax error in your pointer example: type Employee struct { FirstName *string `json:”name”` Salary *int `json:”salary”` FullTime *bool `json:”fullTime”` } So I’ve moved the asterisk to the type, and I’ve captialized the fields. The encoding/json package uses reflection to set … Read more
Embedded types are (unnamed) fields, referred to by the unqualified type name. Spec: Struct types: A field declared with a type but no explicit field name is an anonymous field, also called an embedded field or an embedding of the type in the struct. An embedded type must be specified as a type name T … Read more
There are two distinct dot syntaxes being used here. They look the same, but they do different things depending on what they are operating on and what is being done with it: The first myView.frame is a shorthand for [myView frame], a method call that returns a CGRect struct by value. myFrame.origin.x is accessing ordinary … Read more
There are a couple of ways to do this, but you need to use some macros to either define or adapt the struct. You can use the REFLECTABLE macro given in this answer to define the struct like this: struct A { REFLECTABLE ( (int) a, (int) b, (int) c ) }; And then you … Read more
It depends if you want a pointer or not. It’s better to call your structure like this : typedef struct s_data { int a; char *b; // etc.. } t_data; After to instanciate it for a no-pointer structure : t_data my_struct; my_struct.a = 8; And if you want a pointer you need to malloc it … Read more
& is the string concat operator, AND and && are boolean operators. <cfset myStruct.concatendatedSring = myStruct.string1 & myStruct.string2>