---
name: "getrusage"
section: "2"
platform: "macos"
package: "xnu"
version: "12377.121.6"
release: "macOS 26.5"
platforms: ["linux", "freebsd", "macos"]
url: "https://new.carta.tech/getrusage"
---

# getrusage(2)

get information about resource utilization

## NAME

**getrusage** – get information about resource utilization

## SYNOPSIS

**#include \<sys/resource.h\>**

**#define RUSAGE\_SELF 0**

**#define RUSAGE\_CHILDREN -1**

*int*\

**getrusage**(*int who*, *struct rusage \*r\_usage*);

## DESCRIPTION

**getrusage**() returns information describing the resources utilized by the current process, or all its terminated child processes. The *who* parameter is either RUSAGE\_SELF or RUSAGE\_CHILDREN. The buffer to which *r\_usage* points will be filled in with the following structure:

```
struct rusage {
        struct timeval ru_utime; /* user time used */
        struct timeval ru_stime; /* system time used */
        long ru_maxrss;          /* max resident set size */
        long ru_ixrss;           /* integral shared text memory size */
        long ru_idrss;           /* integral unshared data size */
        long ru_isrss;           /* integral unshared stack size */
        long ru_minflt;          /* page reclaims */
        long ru_majflt;          /* page faults */
        long ru_nswap;           /* swaps */
        long ru_inblock;         /* block input operations */
        long ru_oublock;         /* block output operations */
        long ru_msgsnd;          /* messages sent */
        long ru_msgrcv;          /* messages received */
        long ru_nsignals;        /* signals received */
        long ru_nvcsw;           /* voluntary context switches */
        long ru_nivcsw;          /* involuntary context switches */
};
```

The fields are interpreted as follows:

- *ru\_utime*

  the total amount of time spent executing in user mode.

- *ru\_stime*

  the total amount of time spent in the system executing on behalf of the process(es).

- *ru\_maxrss*

  the maximum resident set size utilized (in bytes).

- *ru\_ixrss*

  an integral value indicating the amount of memory used by the text segment that was also shared among other processes.  This value is expressed in units of kilobytes \* ticks-of-execution.

- *ru\_idrss*

  an integral value of the amount of unshared memory residing in the data segment of a process (expressed in units of kilobytes \* ticks-of-execution).

- *ru\_isrss*

  an integral value of the amount of unshared memory residing in the stack segment of a process (expressed in units of kilobytes \* ticks-of-execution).

- *ru\_minflt*

  the number of page faults serviced without any I/O activity; here I/O activity is avoided by reclaiming a page frame from the list of pages awaiting reallocation.

- *ru\_majflt*

  the number of page faults serviced that required I/O activity.

- *ru\_nswap*

  the number of times a process was swapped out of main memory.

- *ru\_inblock*

  the number of times the file system had to perform input.

- *ru\_oublock*

  the number of times the file system had to perform output.

- *ru\_msgsnd*

  the number of IPC messages sent.

- *ru\_msgrcv*

  the number of IPC messages received.

- *ru\_nsignals*

  the number of signals delivered.

- *ru\_nvcsw*

  the number of times a context switch resulted due to a process voluntarily giving up the processor before its time slice was completed (usually to await availability of a resource).

- *ru\_nivcsw*

  the number of times a context switch resulted due to a higher priority process becoming runnable or because the current process exceeded its time slice.

## NOTES

The numbers  *ru\_inblock* and  *ru\_oublock* account only for real I/O; data supplied by the caching mechanism is charged only to the first process to read or write the data.

## RETURN VALUES

The **getrusage()** function returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indicate the error.

## ERRORS

The **getrusage**() system call will fail if:

- \[EFAULT\]

  The address specified by the *r\_usage* parameter is not in a valid part of the process address space.

- \[EINVAL\]

  The *who* parameter is not a valid value.

## LEGACY SYNOPSIS

**#include \<sys/time.h\>** **#include \<sys/resource.h\>**

The include file ⟨sys/time.h⟩ is necessary.

## SEE ALSO

[gettimeofday(2)](/gettimeofday/2.md), [wait(2)](/wait/2.md), [compat(5)](/compat/5.md)

## BUGS

There is no way to obtain information about a child process that has not yet terminated.

## HISTORY

The **getrusage**() function call appeared in 4.2BSD.