The C17 standard deprecates ATOMIC_VAR_INIT from stdatomic.h, meaning it still supports it but would rather it not be used. What is the correct non-deprecated way of initializing atomics in C17?
Same as non-atomic types:
atomic_int foo = 42;
Or something new?
C17 makes it ok to initialize atomics using the usual explicit initialization:
atomic_int n = 42;
C17 literally just dropped the two words "using ATOMIC_VAR_INIT" from the sentence in 7.17.2.1.
Based on that document, section DR 454, using the macro makes it impossible to know in which state is the variable.
atomic_int guide1 = ATOMIC_VAR_INIT(42); /* known value(42); WHAT STATE? */
But using the normal assignment is also undetermined, as shown bellow.
atomic_int guide2; /* indeterminate value; indeterminate state */
atomic_int guide3 = 42; /* known value(42); indeterminate state */
To put your variable in a known state, you have either to use static or the atomic_init function.
static atomic_int guide4; /* known value(0); valid state */
static atomic_int guide5 = 42; /* known value(42); valid state */
atomic_int guide6;
atomic_init(&guide6, 42); /* known value(42); initialized state */
But that's the only information I could find.
