Corrected and expanded documentation for rand() and srand() functions.

1 files changed, 10 insertions, 7 deletions

diff --git a/doc/expr.n b/doc/expr.n
index f7d49d9..cdb6560 100644
--- a/doc/expr.n
+++ b/doc/expr.n
@@ -5,7 +5,7 @@
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
 '\" 
-'\" RCS: @(#) $Id: expr.n,v 1.9 2002/07/01 18:24:39 jenglish Exp $
+'\" RCS: @(#) $Id: expr.n,v 1.10 2003/01/03 23:03:22 dgp Exp $
 '\" 
 .so man.macros
 .TH expr n 8.4 Tcl "Tcl Built-In Commands"
@@ -280,10 +280,13 @@ Computes the value of \fIx\fR raised to the power \fIy\fR.  If \fIx\fR
 is negative, \fIy\fR must be an integer value.
 .TP
 \fBrand()\fR
-Returns a floating point number from zero to just less than one or, in
-mathematical terms, the range [\fI0\fR,\fI1\fR).  The seed comes from
-the internal clock of the machine or may be set manual with the
-\fBsrand\fR function.
+Returns a pseudo-random floating point value in the range (\fI0\fR,\fI1\fR).  
+The generator algorithm is a simple linear congruential generator that
+is not cryptographically secure.  Each result from \fBrand\fR completely
+determines all future results from subsequent calls to \fBrand\fR, so
+\fBrand\fR should not be used to generate a sequence of secrets, such as
+one-time passwords.  The seed of the generator is initialized from the
+internal clock of the machine or may be set with the \fBsrand\fR function.
 .TP
 \fBround(\fIarg\fB)\fR
 If \fIarg\fR is an integer value, returns \fIarg\fR, otherwise converts
@@ -301,8 +304,8 @@ Returns the square root of \fIarg\fR.  \fIArg\fR must be non-negative.
 .TP
 \fBsrand(\fIarg\fB)\fR
 The \fIarg\fR, which must be an integer, is used to reset the seed for
-the random number generator.  Returns the first random number from
-that seed.  Each interpreter has its own seed.
+the random number generator of \fBrand\fR.  Returns the first random
+number from that seed.  Each interpreter has its own seed.
 .TP
 \fBtan(\fIarg\fB)\fR
 Returns the tangent of \fIarg\fR, measured in radians.