Question

I have compiled an Ada program on Ubuntu using GNAT.

Afterwards, I tried a few test runs with that program and it worked properly.

But when I uploaded this to my Apache (UNIX) webserver and tried to run the program, there was no output. Why is this so?

Could it be that programs which have been compiled on Ubuntu don’t work on a UNIX server?

(Sorry for the stupid question!)

Linux version of the system I use for compiling (uname -a):

Linux ubuntu 3.0.0-12-generic #20-Ubuntu x86-64 GNU/Linux

Linux version of the system I want to run the program on later (uname -a):

Linux 2.6.37-he-xeon-64gb+1 i686 GNU/Linux

For compiling on the Ubuntu machine, I use:

gnatmake -O3 myprogram -bargs -static

Answer 1

When you build a GNAT program (gnatmake my_program), by default it links against dynamic libraries (libgnat.so, libgnarl.so). These libraries are part of the GNAT system and are very unlikely to be available on your web server.

If you say ldd my_program it will show you the shared libraries used.

You can force the build to use the static GNAT libraries by saying

gnatmake my_program -bargs -static

(the -bargs -static must come after regular flags like -O2).

Edit: more info on -bargs and friends.