[#WITH_LOCK]
= WITH_LOCK
:mrdocs:

Run code while locking a mutex.

== Synopsis

Declared in `<sync.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
#define WITH_LOCK(cs, code)

----

== Description

Examples:

WITH_LOCK(cs, shared_val = shared_val + 1);

int val = WITH_LOCK(cs, return shared_val);

Note:

Since the return type deduction follows that of decltype(auto), while the deduced type of:

WITH_LOCK(cs, int i = 1; return i);

is int, the deduced type of:

WITH_LOCK(cs, int j = 1; return (j));

is &int, a reference to a local variable

The above is detectable at compile‐time with the ‐Wreturn‐local‐addr flag in gcc and the ‐Wreturn‐stack‐address flag in clang, both enabled by default.

== Parameters

[cols="1,4"]
|===
| Name| Description
| *cs*
| Mutex to lock while the code runs.
| *code*
| Statements to execute while holding the lock; its value is returned.
|===


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