16. Timer Manager — RTEMS POSIX API Guide 5.4-rc2 (21st August 2026) documentation

# 16. Timer Manager

## 16.1. Introduction

The timer manager is …

The services provided by the timer manager are:

- timer_create - Create a Per-Process Timer

- timer_delete - Delete a Per-Process Timer

- timer_settime - Set Next Timer Expiration

- timer_gettime - Get Time Remaining on Timer

- timer_getoverrun - Get Timer Overrun Count

## 16.2. Background

## 16.3. Operations

## 16.4. System Calls

This section details the timer manager’s services. A subsection is dedicated to each of this manager’s services and describes the calling sequence, related constants, usage, and status codes.

### 16.4.1. timer_create - Create a Per-Process Timer

CALLING SEQUENCE:

    #include <time.h>
    #include <signal.h>
    int timer_create(
        clockid_t        clock_id,
        struct sigevent *evp,
        timer_t         *timerid
    );

STATUS CODES:

`EXXX` -

DESCRIPTION:

NOTES:

### 16.4.2. timer_delete - Delete a Per-Process Timer

CALLING SEQUENCE:

    #include <time.h>
    int timer_delete(
        timer_t timerid
    );

STATUS CODES:

`EXXX` -

DESCRIPTION:

NOTES:

### 16.4.3. timer_settime - Set Next Timer Expiration

CALLING SEQUENCE:

    #include <time.h>
    int timer_settime(
        timer_t                  timerid,
        int                      flags,
        const struct itimerspec *value,
        struct itimerspec       *ovalue
    );

STATUS CODES:

`EXXX` -

DESCRIPTION:

NOTES:

### 16.4.4. timer_gettime - Get Time Remaining on Timer

CALLING SEQUENCE:

    #include <time.h>
    int timer_gettime(
        timer_t            timerid,
        struct itimerspec *value
    );

STATUS CODES:

`EXXX` -

DESCRIPTION:

NOTES:

### 16.4.5. timer_getoverrun - Get Timer Overrun Count

CALLING SEQUENCE:

    #include <time.h>
    int timer_getoverrun(
        timer_t   timerid
    );

STATUS CODES:

`EXXX` -

DESCRIPTION:

NOTES: