From b6119e581e6ea9273b188463dc4529c30db140ba Mon Sep 17 00:00:00 2001
From: Martin Braun <martin.braun@ettus.com>
Date: Tue, 6 Jul 2021 16:51:55 +0200
Subject: uhd: Replace Boost mutexes and locks with standard options

This is a very mechanical task that could almost have been done with
sed. Boost versions of mutexes and locks were removed, and replaced with
std:: versions. The replacement tables are as follows:

== Mutexes ==
- boost::mutex -> std::mutex
- boost::recursive_mutex -> std::recursive_mutex

Mutexes behave identically between Boost and std:: and have the same
API.

== Locks ==
C++11 has only two types of lock that we use/need in UHD:
- std::lock_guard: Identical to boost::lock_guard
- std::unique_lock: Identical to boost::unique_lock

Boost also has boost::mutex::scoped_lock, which is a typedef for
boost::unique_lock<>. However, we often have used scoped_lock where we
meant to use lock_guard<>. The name is a bit misleading, "scoped lock"
sounding a bit like an RAII mechanism. Therefore, some previous
boost::mutex::scoped_lock are now std::lock_guard<>.

std::unique_lock is required when doing more than RAII locking (i.e.,
unlocking, relocking, usage with condition variables, etc.).

== Condition Variables ==
Condition variables were out of the scope of this lock/mutex change, but
in UHD, we inconsistently use boost::condition vs.
boost::condition_variable. The former is a templated version of the
latter, and thus works fine with std::mutex'es. Therefore, some
boost::condition_variable where changed to boost::condition.

All locks and mutexes use `#include <mutex>`. The corresponding Boost
includes were removed. In some cases, this exposed issues with implicit
Boost includes elsewhere. The missing explicit includes were added.
---
 host/lib/usrp/usrp2/io_impl.cpp | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

(limited to 'host/lib/usrp/usrp2/io_impl.cpp')

diff --git a/host/lib/usrp/usrp2/io_impl.cpp b/host/lib/usrp/usrp2/io_impl.cpp
index 792b4721b..a966f91ea 100644
--- a/host/lib/usrp/usrp2/io_impl.cpp
+++ b/host/lib/usrp/usrp2/io_impl.cpp
@@ -92,7 +92,7 @@ public:
      */
     UHD_INLINE bool check_fc_condition(double timeout)
     {
-        boost::mutex::scoped_lock lock(_fc_mutex);
+        std::unique_lock<std::mutex> lock(_fc_mutex);
         if (this->ready())
             return true;
         boost::this_thread::disable_interruption di; // disable because the wait can throw
@@ -105,7 +105,7 @@ public:
      */
     UHD_INLINE void update_fc_condition(seq_type seq)
     {
-        boost::mutex::scoped_lock lock(_fc_mutex);
+        std::unique_lock<std::mutex> lock(_fc_mutex);
         _last_seq_ack = seq;
         lock.unlock();
         _fc_cond.notify_one();
@@ -117,7 +117,7 @@ private:
         return seq_type(_last_seq_out - _last_seq_ack) < _max_seqs_out;
     }
 
-    boost::mutex _fc_mutex;
+    std::mutex _fc_mutex;
     boost::condition _fc_cond;
     seq_type _last_seq_out, _last_seq_ack;
     const seq_type _max_seqs_out;
-- 
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