Re: What exactly does the compiler switch -betterC do?

[Gary Willoughby via Digitalmars-d-learn]

On Monday, 20 June 2016 at 06:35:32 UTC, Jacob Carlborg wrote:
On 2016-06-19 21:53, Gary Willoughby wrote:
When compiling, what exactly does the -betterC flag do? The 
command help
says "omit generating some runtime information and helper 
functions" but
what does this really mean? Is there any specifics somewhere?

It is intended to allow you to link an application without 
druntime. A Hello World using "extern(C) main" and printing 
using "printf" contains the following symbols on OS X:

00000000000000a8 S _D4main12__ModuleInfoZ
0000000000000068 T _D4main15__unittest_failFiZv
0000000000000018 T _D4main7__arrayZ
0000000000000040 T _D4main8__assertFiZv
00000000000000b5 s _TMP1
                 U __d_arraybounds
                 U __d_assert
                 U __d_unittest
0000000000000000 T _main
                 U _printf

If compiled with -betterC, it contains these:

0000000000000000 T _main
                 U _printf

I get significantly more symbols than that when compiling the 
following program any idea why?

    import core.stdc.stdio;

    extern(C) void main()
    {
        printf("Hello World!\n");
    }


$ rdmd --build-only --force -betterC -de -O -inline -release -w 
test.d
$ nm test