pwcache.3

早期freebsd实现

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.\"     @(#)pwcache.3	8.1 (Berkeley) 6/9/93
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.Dd June 9, 1993
.Dt PWCACHE 3
.Os
.Sh NAME
.Nm pwcache
.Nd cache password and group entries
.Sh SYNOPSIS
.Fn user_from_uid "uid_t uid" "int nouser"
.Fn group_from_gid "gid_t gid" "int nogroup"
.Sh DESCRIPTION
.Pp
The
.Fn user_from_uid
function returns the user name associated with the argument
.Fa uid .
The user name is cached so that multiple calls with the same
.Fa uid 
do not require additional calls to
.Xr getpwuid 3 .
If there is no user associated with the
.Fa uid ,
a pointer is returned
to a string representation of the
.Fa uid ,
unless the argument
.Fa nouser
is non-zero, in which case a
.Dv NULL
pointer is returned.
.Pp
The
.Fn group_from_gid
function returns the group name associated with the argument
.Fa gid .
The group name is cached so that multiple calls with the same
.Fa gid
do not require additional calls to
.Xr getgrgid 3 .
If there is no group associated with the
.Fa gid ,
a pointer is returned
to a string representation of the
.Fa gid ,
unless the argument
.Fa nogroup
is non-zero, in which case a
.Dv NULL
pointer is returned.
.Sh SEE ALSO
.Xr getgrgid 3 ,
.Xr getpwuid 3
.Sh HISTORY
The
.Fn user_from_id
and
.Fn group_from_id
functions first appeared in 4.4BSD.