g++ 6.3 build failure is still happening for 5.0.0-rc3

[sflitman]

This is a request to reopen #3255

Environment

• Tesseract Version: 5.00-rc3
• Commit Number: ?
• Platform: Linux server 4.9.0-14-amd64 defect issue #1 SMP Debian 4.9.240-2 (2020-10-30) x86_64 GNU/Linux

Current Behavior: Compile fails after successful configure on Debian Stretch:

Making all in .
make[1]: Entering directory '/dsk/src/tesseract-5.0.0-rc3'
  CXX      src/api/libtesseract_la-baseapi.lo
In file included from ./src/ccutil/elst.h:24:0,
                 from ./src/ccstruct/points.h:22,
                 from ./src/ccstruct/rect.h:22,
                 from ./src/ccstruct/boxword.h:22,
                 from src/api/baseapi.cpp:26:
./src/ccutil/serialis.h: In member function ‘bool tesseract::TFile::DeSerialize(std::vector<T>&)’:
./src/ccutil/serialis.h:107:15: error: expected ‘(’ before ‘constexpr’
     } else if constexpr (std::is_same_v<T, std::string>) {
               ^~~~~~~~~
./src/ccutil/serialis.h:151:3: error: expected ‘}’ at end of input
   }
   ^
./src/ccutil/serialis.h: In member function ‘bool tesseract::TFile::Serialize(const std::vector<T>&)’:
./src/ccutil/serialis.h:166:15: error: expected ‘(’ before ‘constexpr’
     } else if constexpr (std::is_same_v<T, std::string>) {
               ^~~~~~~~~
./src/ccutil/serialis.h:198:3: error: expected ‘}’ at end of input
   }
   ^
In file included from ./src/ccstruct/matrix.h:28:0,
                 from ./src/ccstruct/ratngs.h:31,
                 from ./src/dict/dawg.h:33,
                 from ./src/dict/dawg_cache.h:23,
                 from src/api/baseapi.cpp:28:
./src/ccutil/helpers.h: In function ‘bool tesseract::Serialize(FILE*, const std::vector<T>&)’:
./src/ccutil/helpers.h:255:13: error: expected ‘(’ before ‘constexpr’
   } else if constexpr (std::is_class_v<T>) {
             ^~~~~~~~~
src/api/baseapi.cpp:2365:1: error: expected ‘}’ at end of input
 } // namespace tesseract
 ^
src/api/baseapi.cpp: At global scope:
src/api/baseapi.cpp:2365:1: error: expected ‘}’ at end of input
Makefile:4693: recipe for target 'src/api/libtesseract_la-baseapi.lo' failed
make[1]: *** [src/api/libtesseract_la-baseapi.lo] Error 1
make[1]: Leaving directory '/dsk/src/tesseract-5.0.0-rc3'
Makefile:7798: recipe for target 'all-recursive' failed
make: *** [all-recursive] Error 1

Expected Behavior: Successful compilation with g++ version 6.3

Suggested Fix: Add -std=c++14 to CXXFLAGS, but tried it and it didn't work

It would be nice for my client to get Tesseract working on a server he is afraid to upgrade from Debian Stretch, but I understand if it would be too much work to get it to work for an old OS.
Thanks,
SSF

[stweil]

This is a request to reopen #3255

Then please don't open new issues, but add your comments there.

[amitdo]

Debian Stretch LTS EOL is June 2022. Use 4.1.3 instead of 5.0.0 or upgrade to a newer Debian version.

We are not going to support GCC 6.x in Tesseract 5.0.0.

[amitdo]

Another option:
#3210 (comment)

[sflitman]

Understood, thanks. Now I can ask the client to upgrade! Stephen S. Flitman, MD Medical Director Xenoscience, Inc. 602 274 9500 602 274 5661 fax

…

On Mon, Nov 29, 2021, 07:51 Amit D. ***@***.***> wrote: Debian Stretch LTS EOL is June 2022. Use 4.1.3 instead of 5.0.0 or upgrade to a newer Debian version. We are not going to support GCC 6.x in Tesseract 5.0.0. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#3661 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AA2HUSLR6OGJZIHF6XEL5HTUOOHO3ANCNFSM5I32HNRA> . Triage notifications on the go with GitHub Mobile for iOS <https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android <https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>.