From dce80beb0eb02fb3ab5b06a90f8d8e8ccca4baa9 Mon Sep 17 00:00:00 2001
From: Eisuke Kawashima <e-kwsm@users.noreply.github.com>
Date: Wed, 17 Aug 2022 11:10:24 +0900
Subject: [PATCH] doc: add explanations of OB_RANDOM_SEED environment variable

---
 doc/obabel.1    | 8 ++++++++
 doc/obdistgen.1 | 7 +++++++
 doc/obgen.1     | 7 +++++++
 doc/obrotamer.1 | 7 +++++++
 4 files changed, 29 insertions(+)

diff --git a/doc/obabel.1 b/doc/obabel.1
index 1411ccca1..e5de39c92 100644
--- a/doc/obabel.1
+++ b/doc/obabel.1
@@ -520,6 +520,14 @@ For further specific information and options, use
 .Fl H Ar format-type ,
 e.g.,
 .Fl Hcml
+.Sh ENVIRONMENT
+.Bl -tag -width flag
+.It Ev OB_RANDOM_SEED
+If set and non-null, seed this value to pseudo random number generator;
+otherwise random seed is used.
+This feature is effective if Open Babel is built with \fI-DOB_USE_OBRANDOMMT\fP cpreprocessor flag
+(will be automatically enabled when version 4 is released).
+.El
 .Sh EXAMPLES
 Standard conversion:
 .Dl "obabel ethanol.xyz \-Oethanol.pdb"
diff --git a/doc/obdistgen.1 b/doc/obdistgen.1
index 786acf813..a55e73666 100644
--- a/doc/obdistgen.1
+++ b/doc/obdistgen.1
@@ -9,6 +9,13 @@
 .Ar filename
 .Sh DESCRIPTION
 Generates SDFs with distance geometry.
+.Sh ENVIRONMENT
+.Bl -tag -width flag
+.It Ev OB_RANDOM_SEED
+Seed for pseudo random number generator; random seed is used if unset or null.
+This feature is effective if Open Babel is built with \fI-DOB_USE_OBRANDOMMT\fP CPP flag
+(will be automatically enabled when version 4 is released).
+.El
 .Sh EXAMPLES
 .Dl "obdistgen molecule.smi > molecule.sdf"
 .Pp
diff --git a/doc/obgen.1 b/doc/obgen.1
index 7901865a5..24850ee9e 100644
--- a/doc/obgen.1
+++ b/doc/obgen.1
@@ -24,6 +24,13 @@ will give all options including the available forcefields.
 .It Fl ff Ar forcefield
 Select the forcefield
 .El
+.Sh ENVIRONMENT
+.Bl -tag -width flag
+.It Ev OB_RANDOM_SEED
+Seed for pseudo random number generator; random seed is used if unset or null.
+This feature is effective if Open Babel is built with \fI-DOB_USE_OBRANDOMMT\fP CPP flag
+(will be automatically enabled when version 4 is released).
+.El
 .Sh EXAMPLES
 .Pp
 View the possible options, including available forcefields:
diff --git a/doc/obrotamer.1 b/doc/obrotamer.1
index adc47e4ba..e8d8c434a 100644
--- a/doc/obrotamer.1
+++ b/doc/obrotamer.1
@@ -17,6 +17,13 @@ rotamers are not conformers -- that is,
 does not perform geometry optimization after generating the rotamer
 structure. The obminimize tool can do geometry optimization using
 molecular mechanics.
+.Sh ENVIRONMENT
+.Bl -tag -width flag
+.It Ev OB_RANDOM_SEED
+Seed for pseudo random number generator; random seed is used if unset or null.
+This feature is effective if Open Babel is built with \fI-DOB_USE_OBRANDOMMT\fP CPP flag
+(will be automatically enabled when version 4 is released).
+.El
 .Sh EXAMPLES
 .Dl "obrotamer baseconformer.sdf > rotamer1.sdf"
 .Pp