typedef-ing a struct compared to not typedef-ing a struct.

[Markus]

Are there any major differences between the following, apart from syntactically:

typedef struct {
    /** Struct members */
} stack;
 
struct sstack {
    /** Struct members */
} stack;
 

Thanks,
Mark.

[donbock]

In the first case, "stack" is the name of a type; in the second case, "stack" is the name of a variable.

If you intended to compare these cases:

struct sstruct {
    ....
};
struct sstruct stack1;
 
typedef struct sstruct stack_t;
stack_t stack2;

Then I believe there is no meaningful or useful difference; but I'm eager to see if somebody else is aware of one.

[Markus]

@donbock
Ah. My bad. I was looking at it wrong - when I glanced over it, I thought 'stack' was a variable in both cases. Now I see that it isn't.

[Banfa]

Remember in C++ you don't need to typedef at all the name of the srtuct is automatically defined as a type

struct sstack {
    /** Struct members */
};
 
sstack stack;
 

Valid C++, not valid C.

[Markus]

@Banfa
Oh? I'm sure the book, on C, I was reading just did:

struct struct_name {
    /** ... */
};
 

as a way of defining the struct. I cannot check now as I've taken it back to the library.

I guess VSC++ never picked that up because it doesn't know whether I'm using C++ or C. Speaking of which, is there a way to get VS to work specifically with C? Furthermore, does it matter if I write C code for a C++ compiler?

[Banfa]

It is not the declaration of the structure but the declaration of the variable following that is valid in C++ and not C

sstack stack;

Many C++ compilers also compile C code. Normally the decision on which language to use is based on the file extension .c = C, .cpp and .cxx = C++. However some compilers include switches to force the compilation to C or C++ (something I found particularly useful when I wanted to compile some auto generated C files as C++.

VSC++ and gnu gcc both have switches like this but you will have to check your compiler documentation to find out what they are.

[weaknessforcats]

typedef struct {
/** Struct members */
} stack;

struct sstack {
/** Struct members */
} stack;

There is a huge difference between these two lines of code.

The typedef says that a struct with those members is a type. However, the typedef does not create a stack object. So if you use the typedef to chaange stack members you get program crashes becuse there is no stack variable.