Display the source code in std/process.d from which thispage was generated on github.

If you spot a problem with this page, click here to create aBugzilla issue.

Quickly fork, edit online, and submit a pull request for this page.Requires a signed-in GitHub account. This works well for small changes.If you'd like to make larger changes you may want to consider usinglocal clone.

Function `std.process.environment.opBinaryRight`

Identify whether a variable is defined in the environment.


						
				bool opBinaryRight(string op : "in")(
				
  scope const(char)[] name
				

				) @trusted;

Because it doesn't return the value, this function is cheaper than get. However, if you do need the value as well, you should just check the return of get for null instead of using this function first.

Example

// good usage
if ("MY_ENV_FLAG" in environment)
    doSomething();

// bad usage
if ("MY_ENV_VAR" in environment)
    doSomething(environment["MY_ENV_VAR"]);

// do this instead
if (auto var = environment.get("MY_ENV_VAR"))
    doSomething(var);

Authors

Lars Tandle Kyllingstad, Steven Schveighoffer, Vladimir Panteleev

License

Boost License 1.0.