Merge topic 'HelpEnv'

a693da21f3 Help: from command:if, link to environment variables
ab2bdbaf31 Help: Cross-reference ENV operator from cmake-language(7) manual
ee4e728a69 Help: From Environment Variables section, link to cmake -E env etc

Acked-by: Kitware Robot <kwrobot@kitware.com>
Merge-request: !7239

Help/command/if.rst

@@ -71,8 +71,9 @@ Basic Expressions
  True if given a variable that is defined to a value that is not a false
  constant.  False otherwise, including if the variable is undefined.
  Note that macro arguments are not variables.
- Environment variables also cannot be tested this way, e.g.
- ``if(ENV{some_var})`` will always evaluate to false.
+ :ref:`Environment Variables <CMake Language Environment Variables>` also
+ cannot be tested this way, e.g. ``if(ENV{some_var})`` will always evaluate
+ to false.
 
 ``if(<string>)``
  A quoted string always evaluates to false unless:

Help/manual/cmake-language.7.rst

@@ -582,7 +582,8 @@ Scope
  They are never cached.
 
 References
- `Variable References`_ have the form ``$ENV{<variable>}``.
+ `Variable References`_ have the form ``$ENV{<variable>}``, using the
+ :variable:`ENV` operator.
 
 Initialization
  Initial values of the CMake environment variables are those of
@@ -594,6 +595,13 @@ Initialization
  Changed values are not written back to the calling process,
  and they are not seen by subsequent build or test processes.
 
+ See the :ref:`cmake -E env <Run a Command-Line Tool>` command-line
+ tool to run a command in a modified environment.
+
+Inspection
+ See the :ref:`cmake -E environment <Run a Command-Line Tool>` command-line
+ tool to display all current environment variables.
+
 The :manual:`cmake-env-variables(7)` manual documents environment
 variables that have special meaning to CMake.
 

Help/manual/cmake.1.rst

@@ -619,6 +619,8 @@ in the set of :variable:`CMAKE_ARGV<n> <CMAKE_ARGV0>` variables passed to the
 script (including the ``--`` itself).
 
 
+.. _`Run a Command-Line Tool`:
+
 Run a Command-Line Tool
 =======================
 

Help/variable/ENV.rst

@@ -8,5 +8,6 @@ Use the syntax ``$ENV{VAR}`` to read environment variable ``VAR``.
 To test whether an environment variable is defined, use the signature
 ``if(DEFINED ENV{<name>})`` of the :command:`if` command.
 
-See the :command:`set` and :command:`unset` commands to see how to
-write or remove environment variables.
+For general information on environment variables, see the
+:ref:`Environment Variables <CMake Language Environment Variables>`
+section in the :manual:`cmake-language(7)` manual.