---
name: "times"
section: "2"
platform: "linux"
package: "man-pages"
version: "6.19-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/times/2"
---

# times(2)

get process times

## NAME

times - get process times

## LIBRARY

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

## SYNOPSIS

```
#include <sys/times.h>
```

**clock\_t times(struct tms \****buf***);**

## DESCRIPTION

**times**() stores the current process times in the *struct tms* that *buf* points to. The *struct tms* is as defined in *\<sys/times.h\>*:

```
struct tms {
    clock_t tms_utime;  /* user time */
    clock_t tms_stime;  /* system time */
    clock_t tms_cutime; /* user time of children */
    clock_t tms_cstime; /* system time of children */
};
```

The *tms\_utime* field contains the CPU time spent executing instructions of the calling process. The *tms\_stime* field contains the CPU time spent executing inside the kernel while performing tasks on behalf of the calling process.

The *tms\_cutime* field contains the sum of the *tms\_utime* and *tms\_cutime* values for all waited-for terminated children. The *tms\_cstime* field contains the sum of the *tms\_stime* and *tms\_cstime* values for all waited-for terminated children.

Times for terminated children (and their descendants) are added in at the moment [**wait**(2)](/wait/2.md) or [**waitpid**(2)](/waitpid/2.md) returns their process ID. In particular, times of grandchildren that the children did not wait for are never seen.

All times reported are in clock ticks.

## RETURN VALUE

**times**() returns the number of clock ticks that have elapsed since an arbitrary point in the past. The return value may overflow the possible range of type *clock\_t*. On error, *(clock\_t) -1* is returned, and *errno* is set to indicate the error.

## ERRORS

- **EFAULT**

  *tms* points outside the process's address space.

## VERSIONS

On Linux, the *buf* argument can be specified as NULL, with the result that **times**() just returns a function result. However, POSIX does not specify this behavior, and most other UNIX implementations require a non-NULL value for *buf*.

## STANDARDS

POSIX.1-2024.

## HISTORY

POSIX.1-2001, SVr4, 4.3BSD.

In POSIX.1-1996 the symbol **CLK\_TCK** (defined in *\<time.h\>*) is mentioned as obsolescent. It is obsolete now.

Before Linux 2.6.9, if the disposition of **SIGCHLD** is set to **SIG\_IGN**, then the times of terminated children are automatically included in the *tms\_cstime* and *tms\_cutime* fields, although POSIX.1-2001 says that this should happen only if the calling process [**wait**(2)](/wait/2.md)s on its children. This nonconformance is rectified in Linux 2.6.9 and later.

On Linux, the “arbitrary point in the past” from which the return value of **times**() is measured has varied across kernel versions. On Linux 2.4 and earlier, this point is the moment the system was booted. Since Linux 2.6, this point is *(2^32/HZ) - 300* seconds before system boot time. This variability across kernel versions (and across UNIX implementations), combined with the fact that the returned value may overflow the range of *clock\_t*, means that a portable application would be wise to avoid using this value. To measure changes in elapsed time, use [**clock\_gettime**(2)](/clock_gettime/2.md) instead.

SVr1-3 returns *long* and the struct members are of type *time\_t* although they store clock ticks, not seconds since the Epoch. V7 used *long* for the struct members, because it had no type *time\_t* yet.

## NOTES

The number of clock ticks per second can be obtained using:

```
sysconf(_SC_CLK_TCK);
```

Note that [**clock**(3)](/clock/3.md) also returns a value of type *clock\_t*, but this value is measured in units of **CLOCKS\_PER\_SEC**, not the clock ticks used by **times**().

## BUGS

A limitation of the Linux system call conventions on some architectures (notably i386) means that on Linux 2.6 there is a small time window (41 seconds) soon after boot when **times**() can return -1, falsely indicating that an error occurred. The same problem can occur when the return value wraps past the maximum value that can be stored in **clock\_t**.

## SEE ALSO

[**time**(1)](/time/1.md), [**getrusage**(2)](/getrusage/2.md), [**wait**(2)](/wait/2.md), [**clock**(3)](/clock/3.md), [**sysconf**(3)](/sysconf/3.md), [**time**(7)](/time/7.md)