are encouraged but not required to meet the same semantics
as word-sized memory locations,
observing a single allowed write <i>w</i>.
For performance reasons,
implementations may instead treat larger operations
as a set of individual machine-word-sized operations
in an unspecified order.
This means that races on multiword data structures
can lead to inconsistent values not corresponding to a single write.

(It remains available in <code>math/rand</code>.)
The vast majority of calls to <code>Read</code> should use
<a href="/pkg/crypto/rand/#Read"><code>crypto/rand</code>’s <code>Read</code></a> instead.
Otherwise a custom <code>Read</code> can be constructed using the <code>Uint64</code> method.

<li>The global generator accessed by top-level functions is unconditionally randomly seeded.

The stubs also exist at different "levels", where one test might wire stubs into a specific live implementation.
In the next test that same "live implementation" will be used in a stub version instead.

Not all live services have stubs, but can be added as needed.
</body>

</p>


<h3 id="Blank_identifier">Blank identifier</h3>

<p>
The <i>blank identifier</i> is represented by the underscore character <code>_</code>.
It serves as an anonymous placeholder instead of a regular (non-blank)
identifier and has special meaning in <a href="#Declarations_and_scope">declarations</a>,
as an <a href="#Operands">operand</a>, and in <a href="#Assignments">assignments</a>.
</p>

such a symbol must be defined in a Go source file instead.
Assembly source can still refer to the symbol by name
even without <code>DATA</code> and <code>GLOBL</code> directives.
A good general rule of thumb is to define all non-<code>RODATA</code>
symbols in Go instead of in assembly.
</p>

<p>
Each function also needs annotations giving the location of

</p>


<h3 id="Blank_identifier">Blank identifier</h3>

<p>
The <i>blank identifier</i> is represented by the underscore character <code>_</code>.
It serves as an anonymous placeholder instead of a regular (non-blank)
identifier and has special meaning in <a href="#Declarations_and_scope">declarations</a>,
as an <a href="#Operands">operand</a>, and in <a href="#Assignment_statements">assignment statements</a>.
</p>