[TUHS] why the leading under score added to function names?

[Warner Losh]

And this convention went away with ELF binaries.  No more _foo for function foo.

Also, the fortran compiler would emit entry_ to as to not conflict either.  Made calling C from Fortran, and vice versa, a lot of fun...

Warner

On Feb 20, 2012, at 5:34 PM, Brantley Coile wrote:

> correct.  we could link to assembler code with _entry points and not worry about symbol collisions in the rest of the code. 
> 
> iPhone email
> 
> On Feb 20, 2012, at 6:23 PM, "Dave Horsfall" <dave at horsfall.org> wrote:
> 
>> On Mon, 20 Feb 2012, arnold at skeeve.com wrote:
>> 
>> [...]
>> 
>>> I'm pretty sure this dates back to PDP-11 days.  I'm wondering "why?".
>>> Why did the C compiler prepend an underscore to function names?
>> 
>> Sure was the PDP-11 :-)  I vaguely recall that it was to make sure that
>> user functions did not conflict with predefined assembler functions, as
>> that would be a pain to diagnose (much like having swap overlap root).
>> 
>> -- Dave
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