Experimental Physics and
Industrial Control System

From: Mark Rivers <rivers at cars.uchicago.edu>
Sent: Wednesday, June 14, 2023 9:57 AM
To: Pearson, Matthew <pearsonmr at ornl.gov>; tech-talk at aps.anl.gov
Subject: [EXTERNAL] Re: C++ std problem

 

Hi Mark,

 

Using std::hash with enum types (and PicamParameter is an enum) might be the issue:

https://stackoverflow.com/questions/18837857/cant-use-enum-class-as-unordered-map-key

 

The Galil driver declares a map like:

std::unordered_map<std::string, Source> map

 

And std::string was already supported as a hash type in C++11.

 

Using enum for the hash was fixed in C++14, so for gcc 4.8.5 can you try this and see if it works?

 

USR_CXXFLAGS_Linux += -std=c++1y

 

C++14 is the default for gcc 8.5.0, which might explain why it works on Centos 8.

Cheers,

Matt

 

 

I should add that ADPICam.cpp compiles fine on Centos 8 Stream (gcc 8.5.0). 

 

I have compiled other files that use std::unordered_map on gcc 4.8.5 without problems, for example the EPICS Galil motor controller.

 

Thanks,

Mark

 

 

 

I am trying to build areaDetector/ADPICam on Centos 7 (gcc 4.8.5).  It uses std::unordered_map which I believe was added in C++11.

 

If I compile without this line in the Makefile

USR_CXXFLAGS_Linux += -std=c++11

 

then I get this error, which is expected because it is not using C++11.

 

/usr/bin/g++  -D_GNU_SOURCE -D_DEFAULT_SOURCE           -D_X86_64_  -DUNIX  -Dlinux      -O3 -g   -Wall      -mtune=generic      -m64  -fPIC -I. -I../O.Common -I. -I. -I.. -I../../../include/compiler/gcc -I../../../include/os/Linux -I../../../include      -I/corvette/home/epics/devel/asyn-4-43/include     -I/corvette/home/epics/devel/areaDetector-3-12-1/ADSupport/include/os/Linux -I/corvette/home/epics/devel/areaDetector-3-12-1/ADSupport/include   -I/corvette/home/epics/devel/areaDetector-3-12-1/ADCore/include -I/corvette/usr/local/epics-devel/base-7.0.7/include/compiler/gcc -I/corvette/usr/local/epics-devel/base-7.0.7/include/os/Linux -I/corvette/usr/local/epics-devel/base-7.0.7/include        -c ../ADPICam.cpp

In file included from /usr/include/c++/4.8.2/unordered_map:35:0,

                 from ../ADPICam.h:16,

                 from ../ADPICam.cpp:19:

/usr/include/c++/4.8.2/bits/c++0x_warning.h:32:2: error: #error This file requires compiler and library support for the ISO C++ 2011 standard. This support is currently experimental, and must be enabled with the -std=c++11 or -std=gnu++11 compiler options.

#error This file requires compiler and library support for the \

  ^

In file included from ../ADPICam.cpp:19:0:

../ADPICam.h:546:33: warning: non-static data member initializers only available with -std=c++11 or -std=gnu++11 [enabled by default]

     bool imageThreadKeepAlive = true;

                                 ^

../ADPICam.h:553:5: error: 'unordered_map' in namespace 'std' does not name a type

     std::unordered_map<PicamParameter, int> parameterExistsMap;

 

 

If I use the c++11 flag then I get this error:

 

make[1]: Entering directory `/home/epics/devel/areaDetector-3-12-1/ADPICam/PICamApp/src/O.linux-x86_64'

/usr/bin/g++  -D_GNU_SOURCE -D_DEFAULT_SOURCE           -D_X86_64_  -DUNIX  -Dlinux      -O3 -g   -Wall     -std=c++11  -mtune=generic      -m64  -fPIC -I. -I../O.Common -I. -I. -I.. -I../../../include/compiler/gcc -I../../../include/os/Linux -I../../../include      -I/corvette/home/epics/devel/asyn-4-43/include     -I/corvette/home/epics/devel/areaDetector-3-12-1/ADSupport/include/os/Linux -I/corvette/home/epics/devel/areaDetector-3-12-1/ADSupport/include   -I/corvette/home/epics/devel/areaDetector-3-12-1/ADCore/include -I/corvette/usr/local/epics-devel/base-7.0.7/include/compiler/gcc -I/corvette/usr/local/epics-devel/base-7.0.7/include/os/Linux -I/corvette/usr/local/epics-devel/base-7.0.7/include        -c ../ADPICam.cpp

In file included from /usr/include/c++/4.8.2/bits/hashtable.h:35:0,

                 from /usr/include/c++/4.8.2/unordered_map:47,

                 from ../ADPICam.h:16,

                 from ../ADPICam.cpp:19:

/usr/include/c++/4.8.2/bits/hashtable_policy.h: In instantiation of 'struct std::__detail::_Hash_code_base<PicamParameter, std::pair<const PicamParameter, int>, std::__detail::_Select1st, std::hash<PicamParameter>, std::__detail::_Mod_range_hashing, std::__detail::_Default_ranged_hash, true>':

/usr/include/c++/4.8.2/bits/hashtable_policy.h:1402:10:   required from 'struct std::__detail::_Hashtable_base<PicamParameter, std::pair<const PicamParameter, int>, std::__detail::_Select1st, std::equal_to<PicamParameter>, std::hash<PicamParameter>, std::__detail::_Mod_range_hashing, std::__detail::_Default_ranged_hash, std::__detail::_Hashtable_traits<true, false, true> >'

/usr/include/c++/4.8.2/bits/hashtable.h:174:11:   required from 'class std::_Hashtable<PicamParameter, std::pair<const PicamParameter, int>, std::allocator<std::pair<const PicamParameter, int> >, std::__detail::_Select1st, std::equal_to<PicamParameter>, std::hash<PicamParameter>, std::__detail::_Mod_range_hashing, std::__detail::_Default_ranged_hash, std::__detail::_Prime_rehash_policy, std::__detail::_Hashtable_traits<true, false, true> >'

/usr/include/c++/4.8.2/bits/unordered_map.h:100:18:   required from 'class std::unordered_map<PicamParameter, int>'

../ADPICam.h:553:45:   required from here

/usr/include/c++/4.8.2/bits/hashtable_policy.h:1070:12: error: invalid use of incomplete type 'struct std::hash<PicamParameter>'

     struct _Hash_code_base<_Key, _Value, _ExtractKey, _H1, _H2,

            ^

In file included from /usr/include/c++/4.8.2/bits/basic_string.h:3033:0,

                 from /usr/include/c++/4.8.2/string:52,

                 from /usr/include/c++/4.8.2/random:41,

                 from /usr/include/c++/4.8.2/bits/stl_algo.h:65,

                 from /usr/include/c++/4.8.2/algorithm:62,

                 from ../ADPICam.cpp:11:

/usr/include/c++/4.8.2/bits/functional_hash.h:58:12: error: declaration of 'struct std::hash<PicamParameter>'

     struct hash;

            ^

In file included from /usr/include/c++/4.8.2/bits/hashtable.h:35:0,

                 from /usr/include/c++/4.8.2/unordered_map:47,

                 from ../ADPICam.h:16,

                 from ../ADPICam.cpp:19:

/usr/include/c++/4.8.2/bits/hashtable_policy.h:1070:12: error: invalid use of incomplete type 'struct std::hash<PicamParameter>'

     struct _Hash_code_base<_Key, _Value, _ExtractKey, _H1, _H2,

            ^

In file included from /usr/include/c++/4.8.2/bits/basic_string.h:3033:0,

                 from /usr/include/c++/4.8.2/string:52,

                 from /usr/include/c++/4.8.2/random:41,

                 from /usr/include/c++/4.8.2/bits/stl_algo.h:65,

                 from /usr/include/c++/4.8.2/algorithm:62,

                 from ../ADPICam.cpp:11:

/usr/include/c++/4.8.2/bits/functional_hash.h:58:12: error: declaration of 'struct std::hash<PicamParameter>'

     struct hash;

 

Can anyone explain what that error means, and is it possible to use gcc 4.8.5 to compile this file?

 

Mark