30 Dec
2017
30 Dec
'17
1:28 a.m.
On 12/29/17, Wesley Parish <wobblygong(a)gmail.com> wrote:
Which raised the question: when did header files come into use? Who
was the first to use header files to store common system-wide or
application-wide data definitions? Was it used in any languages prior
to C?
It probably all started with macro-instructions (macros) in assembly
languages. The assembler for System/360 in the 1960s had a pretty
complex and powerful conditional assembly and macro expansion
capability. That technology I'm sure dates back to the 1950s.
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.
-Paul W.