diff options
| -rw-r--r-- | doc/expr.n | 17 |
1 files changed, 10 insertions, 7 deletions
@@ -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. |