I am doing the following in C
#define MAX_DATA_SIZE 500;
struct reliable_state {
char dataBuffer[MAX_DATA_SIZE];
}
i.e I want to use the #define constant as array size in structure declaration. But above code gives weird error
.c:36: error: expected ‘]’ before ‘;’ token
So is there any other way to do this?
Yes you can, just remove ';' in your define line:
#define MAX_DATA_SIZE 500
With define you have compiler will actually 'see' your struct definition as
char dataBuffer[500;];
which is clearly erroneous.
When you use #define, the macro on the right side is defined "as is". E.g. here, you've just have to correct it to
#define MAX_DATA_SIZE 500 /* no semicolon */
The syntax for a non-empty object-like macro definitions is
#define MACRO_IDENTIFIER REPLACEMENT
Note that there is no terminating semicolon in this syntax, unlike for C declarations and statements. Your semicolon became part of the REPLACEMENT and was inserted where you used the macro identifier, yielding
char dataBuffer[500;];
which is a syntax error the compiler diagnosed.
#defineline. It should be#define MAX_DATA_SIZE 500