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-rw-r--r--lib/libc/gen/getbsize.338
1 files changed, 27 insertions, 11 deletions
diff --git a/lib/libc/gen/getbsize.3 b/lib/libc/gen/getbsize.3
index 1407051..5a759da 100644
--- a/lib/libc/gen/getbsize.3
+++ b/lib/libc/gen/getbsize.3
@@ -28,12 +28,12 @@
.\" @(#)getbsize.3 8.1 (Berkeley) 6/4/93
.\" $FreeBSD$
.\"
-.Dd June 4, 1993
+.Dd November 16, 2012
.Dt GETBSIZE 3
.Os
.Sh NAME
.Nm getbsize
-.Nd get user block size
+.Nd get preferred block size
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
@@ -43,11 +43,31 @@
.Sh DESCRIPTION
The
.Fn getbsize
-function determines the user's preferred block size based on the value of the
-.Dq BLOCKSIZE
-environment variable; see
-.Xr environ 7
-for details on its use and format.
+function returns a preferred block size for reporting by system utilities
+.Xr df 1 ,
+.Xr du 1 ,
+.Xr ls 1
+and
+.Xr systat 1 ,
+based on the value of the
+.En BLOCKSIZE
+environment variable.
+.En BLOCKSIZE
+may be specified directly in bytes, or in multiples of a kilobyte by
+specifying a number followed by ``K'' or ``k'', in multiples of a
+megabyte by specifying a number followed by ``M'' or ``m'' or in
+multiples of a gigabyte by specifying a number followed by ``G'' or
+``g''.
+Multiples must be integers.
+.Pp
+Valid values of
+.En BLOCKSIZE
+are 512 bytes to 1 gigabyte.
+Sizes less than 512 bytes are rounded up to 512 bytes, and sizes
+greater than 1 GB are rounded down to 1 GB.
+In each case
+.Fn getbsize
+produces a warning message.
.Pp
The
.Fn getbsize
@@ -61,10 +81,6 @@ terminating null).
The memory referenced by
.Fa blocksizep
is filled in with block size, in bytes.
-.Pp
-If the user's block size is unreasonable, a warning message is
-written to standard error and the returned information reflects
-a block size of 512 bytes.
.Sh SEE ALSO
.Xr df 1 ,
.Xr du 1 ,
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