File syn_timeout.h¶

FileList > src > syntropic > util > syn_timeout.h

Non-blocking timeout helper — tick wrap-around safe. More...

#include "../common/syn_defs.h"
#include "../port/syn_port_system.h"
#include <stdbool.h>

Classes¶

Type	Name
struct	SYN_Timeout Non-blocking timeout — tick wrap-around safe.

Public Static Functions¶

Type	Name
uint32_t	syn_timeout_elapsed (const SYN_Timeout * to) Get the elapsed time since the timeout was started.
bool	syn_timeout_expired (const SYN_Timeout * to) Check if the timeout has expired.
bool	syn_timeout_periodic (SYN_Timeout * to) Check expiry and auto-restart if expired (periodic use).
uint32_t	syn_timeout_remaining (const SYN_Timeout * to) Get the remaining time until expiry.
void	syn_timeout_restart (SYN_Timeout * to) Restart the timeout from now with the same duration.
void	syn_timeout_start (SYN_Timeout * to, uint32_t duration) Start (or restart) a timeout.

Macros¶

Type	Name
define	PT_WAIT_TIMEOUT (pt, to) `[PT\_WAIT\_UNTIL](syn__pt_8h.md#define-pt_wait_until)(pt, [syn\_timeout\_expired](syn__timeout_8h.md#function-syn_timeout_expired)(to))` Block a protothread until the timeout expires.

Detailed Description¶

The "has N ms elapsed?" pattern is used everywhere in embedded code and is easy to get wrong with tick counter wrap-around. This header provides a tiny inline API that handles it correctly.

Header-only — zero code size if unused.

** **

SYN_Timeout to;
syn_timeout_start(&to, 1000);

while (!syn_timeout_expired(&to)) {
    // try something...
}

// In a protothread:
PT_WAIT_TIMEOUT(pt, &to);

Public Static Functions Documentation¶

function syn_timeout_elapsed¶

Get the elapsed time since the timeout was started.

static inline uint32_t syn_timeout_elapsed (
    const SYN_Timeout * to
)

Parameters:

to Timeout.

Returns:

Elapsed milliseconds.

function syn_timeout_expired¶

Check if the timeout has expired.

static inline bool syn_timeout_expired (
    const SYN_Timeout * to
)

Uses unsigned subtraction, which is wrap-around safe for a single wrap of the 32-bit tick counter (~49 days at 1 kHz).

Parameters:

to Timeout to check.

Returns:

true if the timeout has expired.

function syn_timeout_periodic¶

Check expiry and auto-restart if expired (periodic use).

static inline bool syn_timeout_periodic (
    SYN_Timeout * to
)

Useful in main loops: "every N ms, do X".

Parameters:

to Timeout.

Returns:

true if the timeout expired (and was restarted).

function syn_timeout_remaining¶

Get the remaining time until expiry.

static inline uint32_t syn_timeout_remaining (
    const SYN_Timeout * to
)

Parameters:

to Timeout.

Returns:

Remaining milliseconds, or 0 if already expired.

function syn_timeout_restart¶

Restart the timeout from now with the same duration.

static inline void syn_timeout_restart (
    SYN_Timeout * to
)

Parameters:

to Timeout.

function syn_timeout_start¶

Start (or restart) a timeout.

static inline void syn_timeout_start (
    SYN_Timeout * to,
    uint32_t duration
)

Parameters:

to Timeout to start.
duration Duration in milliseconds.

Macro Definition Documentation¶

define PT_WAIT_TIMEOUT¶

Block a protothread until the timeout expires.

#define PT_WAIT_TIMEOUT (
    pt,
    to
) `PT_WAIT_UNTIL (pt, syn_timeout_expired (to))`

The documentation for this class was generated from the following file src/syntropic/util/syn_timeout.h