Re: Executable File Size Differences

[dewar@schonberg.cs.nyu.edu (Robert Dewar)]

Stanley said

"The problem is an old one: the lack of "smart linkers" which

would include only the necessary code from an Ada package, and

avoid linking in the unused bulk that never gets invoked.
"

In the case of GNAT, whether or not unused subprograms get eliminated
is a funcytion of the system linkers, since standard object file formats
are used. On some sysetms they will, on many they will not. In any case
the situation will be the same for Ada as for C.

In practice we find that the size of executables is reasonably comparable
with C. I assume no one is tryingf to sell Hello World programs for the
PC, so that comparison is hardly significant. With programs of reasonable
size, the code sizes are comparable. The difference you see between
Hello Wolrd in GNAT (about 55K bytes) and C (10K bytes) is, as I said
earlier, due to the static linking in GNAT vs DLL linking in C, and also
the fact that more of the standard functionality is brought in for a 
simple program (that's because Text_IO has a lot of capability that
the corresponding C routines do not).

But once you get to larger programs, that 40K bytes becomes an unimportant
difference.