Our application (a bunch of PHP scripts and C programs) currently runs on a 64-bit Suse Linux Enterprise Server 10 (yeah, very old) on a physical machine. We are planning to migrate everything to VMware virtual machine that will be running the 64-bit SLES 12. I am aware that there would be compatibility issues between the new PHP on SLES 12 and the existing PHP scripts. My questions are about C programs:
Do we have to re-compile the code again to make it compatible with the libraries available with the new OS?
As far as I can see, there will be no need to touch the C code. Can experts confirm?
Do we have to touch the header files called in the original C source code?
Anything else that we should be taking care of with regards to the C programs?
Pardon this newbie question.
Most likely yes, since programs are linked against specific library versions.
It depends on the code itself. If it uses any deprecated library functions, then those need to be replaced with other ways of doing the same things. Deprecated functions are rare though.
Same as 2.
This is a generic advice on C programs, not related to the upgrade itself. Security issues are always good to be aware of. If those C programs process any user input received from a web site visitor, then the code has to have proper safeguards to prevent buffer overflows and other attacks.