Sorry for asking this, as I’m sure it’s been answered, but I’ve tried searching different terms for the last 30 minutes with no luck finding a definition similar to this.
struct {
volatile uint8_t tail;
uint8_t buf[128];
} uart = {0,0};
In the definition of the structure above, I do not understand what the purpose is of "= {0,0}" at the end.
What is this called? What is its purpose?
If I were to venture a guess, it’s some sort of default value initializer, guessing it sets tail to 0 and the array is 0 filled when a new variable of "uart" type is defined. This is probably a duplicate of some question and I missed a keyword needed for it.
Edit:
Just had another idea… Is this some sort of in-line struct definition and initializing a variable called uart? IE, it doesn’t define a struct named uart, but defines a variable called uart, in-lines the struct definition, then sets the values. Very unusual, if so. I’ve never thought of in-lining a struct definition.
>Solution :
There is no default initialization in C as C objects do not have constructors.
The only exception: not initialized static storage duration objects which are zeroed.
uart = {0,0};
It implicity initializes uart variable with two zeroes. It is better to write it {0, {0,}} as the second member is an erray.