Why doesn't typedef work here?

Question

I know a simple typedef definition:

typedef is a keyword in C to assign alternative names to types.

Following this definition, I tried to implement typedef as follows:

int main()
{
    typedef long mylong; //as per my knowledge after this statement mylong will be treated as long

    int long b;  // this works fine
    int mylong c; // but this gives error
}

I tried this on gcc. And the next error is

I know that this error means that I did not get a real concept of typedef. Can someone please tell me where I am going wrong?

Answer 1

In contrast #define, it typedefis a mechanism for introducing a new name for a type, as opposed to textual substitution.

, long int, int long long - , C. typedef, , .

mylong x = 123;

: mylong . , int, ,

int mylong x = 123;

, int mylong . , , int float x = 5 struct mystruct int z = ....

Answer 2

C, , int

, typedef long mylong; typedef long int mylong;.

:

int long int c;

, .

typedef - * ( long). int . mylong c; .

_{* , , . long int, .}

Answer 3

2 () 6.7.2 C

...

— void
— char
— signed char
— unsigned char
— short, signed short, short int, or signed short int
— unsigned short, or unsigned short int
— int, signed, or signed int
— unsigned, or unsigned int
— long, signed long, long int, or signed long int
— unsigned long, or unsigned long int
— long long, signed long long, long long int, or
signed long long int
— unsigned long long, or unsigned long long int
— float
— double
— long double
— _Bool
— float _Complex
— double _Complex
— long double _Complex
— atomic type specifier
— struct or union specifier
— enum specifier
— typedef name

, C- typedef name .

Answer 4

long/short.

typedef long mylong;

You said: typedef is a keyword in C to assign alternative names to types . " longnot really a type - it's a type. C just lets you leave when using , or so, your statement is equal to long intintshortlonglong long

typedef long int mylong;