diff --color -Naru a/drivers/esci/verify.cpp b/drivers/esci/verify.cpp
--- a/drivers/esci/verify.cpp	2021-02-26 18:46:11.340927936 +0100
+++ b/drivers/esci/verify.cpp	2021-02-26 18:47:41.438929952 +0100
@@ -58,6 +58,7 @@
 
 using namespace utsushi;
 using namespace _drv_::esci;
+using namespace boost::placeholders;
 
 using std::basic_string;
 using std::ios_base;
diff --color -Naru a/gtkmm/pump.cpp b/gtkmm/pump.cpp
--- a/gtkmm/pump.cpp	2021-02-26 18:46:11.344927936 +0100
+++ b/gtkmm/pump.cpp	2021-02-26 18:47:21.566929507 +0100
@@ -31,6 +31,8 @@
 namespace utsushi {
 namespace gtkmm {
 
+using namespace boost::placeholders;
+
 pump::pump (idevice::ptr idev)
   : utsushi::pump (idev)
   , idev_ptr_(idev)
diff --color -Naru a/lib/monitor.cpp b/lib/monitor.cpp
--- a/lib/monitor.cpp	2021-02-26 18:46:11.345927936 +0100
+++ b/lib/monitor.cpp	2021-02-26 18:46:44.906928687 +0100
@@ -48,6 +48,7 @@
 
 namespace utsushi {
 
+using namespace boost::placeholders;
 using boost::filesystem::exists;
 
 class monitor::impl
diff --color -Naru a/sane/handle.cpp b/sane/handle.cpp
--- a/sane/handle.cpp	2021-02-26 18:46:11.347927936 +0100
+++ b/sane/handle.cpp	2021-02-26 18:47:56.758930294 +0100
@@ -57,6 +57,8 @@
 #include "log.hpp"
 #include "value.hpp"
 
+using namespace boost::placeholders;
+
 using std::exception;
 using std::runtime_error;
 using utsushi::_flt_::bottom_padder;