Enum StackSizeClass 

pub enum StackSizeClass {
    Small,
    Medium,
    Big,
}

Stack-size class — epicsThreadStackSizeClass (epicsThread.h:91).

The byte size is implementation-dependent in C. These mirror the POSIX table STACK_SIZE(f) = f * 0x10000 * sizeof(void*) (libcom/src/osi/os/posix/osdThread.c:506-509), pointer-width parameterised exactly as the C macro is: Small = 1, Medium = 2, Big = 4 units of 0x10000 * sizeof(void*). On a 64-bit host that is 512 KiB / 1 MiB / 2 MiB; on armv7-rtems-eabihf it is 256 KiB / 512 KiB / 1 MiB.

This is the table a C IOC on RTEMS 6 uses too

Base has a second, much smaller table — 5000 / 8000 / 11000 bytes, floored at RTEMS_MINIMUM_STACK_SIZE — in os/RTEMS-score/osdThread.c:136-150. It does not apply here. configure/toolchain.c:29-35 selects OS_API = posix for __RTEMS_MAJOR__ >= 5, so an RTEMS 6 build searches os/RTEMS-posix then os/RTEMS, neither of which contains an osdThread.c, and lands on os/posix/osdThread.c — the file above. The score table is what RTEMS 4/5 used.

Do not “align” these constants with 5000/8000/11000. That would be a regression against the C IOC we are matching, not a correction: on RTEMS 6 the C IOC asks pthread_attr_setstacksize for the POSIX number (os/posix/osdThread.c:212-215), which is the same call std makes for us, with the same argument.

Variants

Small

Medium

Big

Implementations

impl StackSizeClass

pub fn bytes(self) -> usize

Stack size in bytes for this class, matching the POSIX stackSizeTable in osdThread.c on every target.

C’s STACK_SIZE(f) = f * 0x10000 * sizeof(void*) is parameterised by pointer width and so is this, so the two agree by construction rather than on one word size: 512 KiB / 1 MiB / 2 MiB on a 64-bit host, and 256 KiB / 512 KiB / 1 MiB on armv7-rtems-eabihf — which is exactly what a C IOC asks pthread_attr_setstacksize for on that target.

Read “on a 64-bit target” here before: it was wrong in the direction that matters, because it invited a reader to assume the RTEMS numbers were unverified. This crate is portable to 64-bit embedded targets too — x86_64-wrs-vxworks — and pays for it: a 64-bit pointer doubles every class in this table, so an x86_64-wrs-vxworks CA client thread costs exactly 2× what the same thread costs on armv7-rtems-eabihf, pointer width for pointer width, not a difference in the formula.

Trait Implementations

impl Clone for StackSizeClass

fn clone(&self) -> StackSizeClass

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for StackSizeClass

impl Debug for StackSizeClass

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Eq for StackSizeClass

impl PartialEq for StackSizeClass

fn eq(&self, other: &StackSizeClass) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for StackSizeClass