---
name: "pwcache"
section: "3"
platform: "macos"
package: "Libc"
version: "1752.120.2"
release: "macOS 26.5"
platforms: ["freebsd", "macos"]
url: "https://new.carta.tech/pwcache"
---

# pwcache(3)

cache password and group entries

## NAME

**pwcache** – cache password and group entries

## LIBRARY

Standard C Library (libc, -lc)

## SYNOPSIS

**#include \<pwd.h\>**

*char* *\**\

**user\_from\_uid**(*uid\_t uid*, *int nouser*);

**#include \<grp.h\>**

*char* *\**\

**group\_from\_gid**(*gid\_t gid*, *int nogroup*);

## DESCRIPTION

The **user\_from\_uid**() function returns the user name associated with the argument *uid*. The user name is cached so that multiple calls with the same *uid* do not require additional calls to [getpwuid(3)](/getpwuid/3.md). If there is no user associated with the *uid*, a pointer is returned to a string representation of the *uid*, unless the argument *nouser* is non-zero, in which case a NULL pointer is returned.

The **group\_from\_gid**() function returns the group name associated with the argument *gid*. The group name is cached so that multiple calls with the same *gid* do not require additional calls to [getgrgid(3)](/getgrgid/3.md). If there is no group associated with the *gid*, a pointer is returned to a string representation of the *gid*, unless the argument *nogroup* is non-zero, in which case a NULL pointer is returned.

## SEE ALSO

[getgrgid(3)](/getgrgid/3.md), [getpwuid(3)](/getpwuid/3.md)

## HISTORY

The **user\_from\_uid**() and **group\_from\_gid**() functions first appeared in 4.4BSD.