[TUHS] origin of C header files

[Clem Cole]

On Fri, Dec 29, 2017 at 2:28 PM, Paul Winalski <paul.winalski at gmail.com>
wrote:

>
> When higher-level languages came along, programmers moving from
> assembly code to a HLL would want the same sort of preprocessor
> functionality.  I know that IBM PL/I had %include, and I suspect that
> other HLLs of the day had similar features.
>
> What's very clear is that C did not invent include files or
> conditional compilation, it merely carried on existing tradition.
>


​I'll +1 Paul's comment and add a couple of observations.   Languages such
a PL/1 and FORTRAN would could support a preprocessor and conditional
compilation, were more easy to use to build 'products' - as opposed to
Pascal.    Folks did splice an backwards conditi​onal compiling scheme with
include files into some Pascal flavors but it was non-standard.

Fortran folks used tools like RATFOR or m4, but the key was the there was
some why to preprocess code for different targets.   In a production shop,
particularly where your 'target' customer was different, this ability
becomes more and more of an requirement.

I've always said as contemporary production systems programming languages,
while BLISS had a better Macro system then C, the include file and
conditional scheme worked much better/was much cleaner - to the point that
ifdef is abused and the cause of much pain in actual code.   But the truth
is that is a success problem.   When used properly, the C header scheme,
while not invented by the BTL crew, was pretty much what people needed.
 No too fancy, but all the features you really needed and has been lasting.

Clem
ᐧ
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