Hi Sudhir,
your question is missing a lot of additional information which would be required to properly answer it.
If your application is compiled for AIX 7.1, it should work without any modifications on AIX 7.3. You don't need to recompile it only because you want to run it on AIX 7.3.
In UNIX environments Makefiles are usually used instead of "Compilation Scripts". You usually don't need any changes to the Makefiles. You check out the source code on AIX 7.3 and start make. It executes the commands to build your software and it is built on AIX 7.3. Sometimes other build configuration systems are used like cmake or ninja. You as developer can look at your code and find it out.
Because you write about "C++ Version 17" and AIX 7.1 and 7.3, I can guess (but only guess) that your application was built on AIX 7.1 using IBM XL C/C++ Compiler V13 or V16. Now you installed IBM Open XL C++ Compiler V17 on AIX 7.3 and your build fails. It is because the "classic" XL C/C++ Compiler and new OpenXL C++ Compiler use different command line options. In this IBM's guide you can find resource what was changed between two versions and how to migrate your code and your building process to OpenXL C++ Compiler.
I hope it helps.
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Andrey Klyachkin
https://www.power-devops.com
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