---
name: "__ppc_get_timebase"
section: "3"
platform: "linux"
package: "man-pages"
version: "6.19-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/__ppc_get_timebase"
---

# \_\_ppc\_get\_timebase(3)

get the current value of the Time Base Register on Power architecture and its frequency.

## NAME

\_\_ppc\_get\_timebase, \_\_ppc\_get\_timebase\_freq - get the current value of the Time Base Register on Power architecture and its frequency.

## LIBRARY

Standard C library (*libc*, *-lc*)

## SYNOPSIS

```
#include <sys/platform/ppc.h>
```

**uint64\_t \_\_ppc\_get\_timebase(void);** **uint64\_t \_\_ppc\_get\_timebase\_freq(void);**

## DESCRIPTION

**\_\_ppc\_get\_timebase**() reads the current value of the Time Base Register and returns its value, while **\_\_ppc\_get\_timebase\_freq**() returns the frequency in which the Time Base Register is updated.

The Time Base Register is a 64-bit register provided by Power Architecture processors. It stores a monotonically incremented value that is updated at a system-dependent frequency that may be different from the processor frequency.

## RETURN VALUE

**\_\_ppc\_get\_timebase**() returns a 64-bit unsigned integer that represents the current value of the Time Base Register.

**\_\_ppc\_get\_timebase\_freq**() returns a 64-bit unsigned integer that represents the frequency at which the Time Base Register is updated.

## STANDARDS

GNU.

## HISTORY

- **\_\_ppc\_get\_timebase**()

  glibc 2.16.

- **\_\_ppc\_get\_timebase\_freq**()

  glibc 2.17.

## EXAMPLES

The following program will calculate the time, in microseconds, spent between two calls to **\_\_ppc\_get\_timebase**().

### Program source

```
#include <inttypes.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/platform/ppc.h>
/* Maximum value of the Time Base Register: 2^60 - 1.
   Source: POWER ISA.  */
#define MAX_TB 0xFFFFFFFFFFFFFFF
int
main(void)
{
    uint64_t tb1, tb2, diff;
    uint64_t freq;
    freq = __ppc_get_timebase_freq();
    printf("Time Base frequency = %w64u Hz\n", freq);
    tb1 = __ppc_get_timebase();
    // Do some stuff...
    tb2 = __ppc_get_timebase();
    if (tb2 > tb1) {
        diff = tb2 - tb1;
    } else {
        /* Treat Time Base Register overflow.  */
        diff = (MAX_TB - tb2) + tb1;
    }
    printf("Elapsed time  = %1.2f usecs\n",
           (double) diff * 1000000 / freq);
    exit(EXIT_SUCCESS);
}
```

## SEE ALSO

[**time**(2)](/time/2.md), [**usleep**(3)](/usleep/3.md)