Re: Compiling and linking code from different places in the file system

From	Rod Pemberton <NoEmail@trraxvfeqa.prg>
Newsgroups	comp.lang.misc
Subject	Re: Compiling and linking code from different places in the file system
Date	2018-03-06 06:39 -0500
Organization	Aioe.org NNTP Server
Message-ID	<p7luil$2d5$1@gioia.aioe.org> (permalink)
References	<p793c8$7d8$1@dont-email.me>

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On Thu, 1 Mar 2018 14:40:07 +0000
James Harris <james.harris.1@gmail.com> wrote:

[c.l.c. dropped]

> It is normal in C programming for any source file which exports 
> identifiers to have an associated header file which /describes/ the 
> identifiers the source exports.

Is it? ...

I would not use the word "normal".  Perhaps "common" or "typical"?

AISI, it's just as likely to not be the case too, i.e., 50-50 or 60-40.

> For example, in a folder called PP
> then the two files might be named
> 
>    PP/SS.c  (the source)
>    PP/SS.h  (the header describing SS.c's exports)
> 
> When another source file, say UU.c, imports an identifier that SS.c 
> exports it would naturally contain a statement which brings in the 
> header at compile time.
> 
>    UU.c
>      #include "SS.h"
> 
> Because C has no concept of a hierarchical namespace here, i.e. the 
> source file cannot say "include PP/SS.h" or "include SS.h from folder 
> PP", the compiler has to be told about folder PP so it looks in it
> for the header.

What? ...

E.g., from Linux stdio.h, where bits is a sub-directory of the include
directory:

#include <bits/sys_errlist.h>

As most C compilers accept standard directory paths in the #include
field, I would think you should be able to use '.' and '..' to refer to
the current and up-directory.

E.g., from Linux mp4ffint.h:

#include "../../config.h"

> And that leads to my first query. (Yes, there is
> one!) If a given source file SS.c includes many headers, and the
> headers could be scattered to the four winds - i.e. distributed
> around the file system - in a really big project what's a good way of
> specifying where the compiler should look for included headers?

It shouldn't.

When the compiler is allowed to decide where to look, it may look in
the wrong place.

The programmer should duplicate the includes or exports locally.  While
this requires more maintenance and could lead to coding mistakes, i.e.,
syncing issues, it ensures that the correct includes or exports are
used, but if and only if, no mistakes are made.

> One options is, of course, to use a separate compile command for each 
> source file. But that could end up being a bit cumbersome. And it
> would 
> - at least ostensibly - prevent automatic generation of the compile 
> commands - which is what I am essentially intending to do.

Are you trying to or trying not to generate the compile commands
automatically?

If it's a truly large project, there could be a dozen SS.h's spread all
about the place.  How do you intend to rectify finding the correct
SS.h?  There is no way you can do this automatically, unless the
correct version of SS.h is placed in every directory where it is used,
i.e., copied or linked to.

> At the moment I normally take the easy route and keep all the source 
> code for a given project in just one one folder or in a few folders.
> But as projects get larger that approach does not scale at all well,
> and I need to improve both how I lay out project code

Many files in a single directory doesn't scale well? ...
(I'm quite not sure what to say to that.  What is scaling here? file
size? file quantity? It's not directories.)

Obviously, you only need to copy or move the .o files together in a
clean way to be linked, after traversing the sub-directories to compile
the code.  Isn't this what a makefile does?

> especially what I do when one project needs to import files from
> another.

The first option is to use code duplication.  It's much easier to just
copy the code from one project into another, than it is to link to it,
if licensing allows.  Now, both projects separate and have what they
need to compile.

Alternately, create a library to link to.  The library can be specified
at compile time via compiler flags.  I'm not sure how that helps with
the #includes or search paths.

Rod Pemberton
-- 
feeback loop:  Russian aggression -> World complains -> Russian
paranioa -> Russian threats -> repeat

Thread

Compiling and linking code from different places in the file system James Harris <james.harris.1@gmail.com> - 2018-03-01 14:40 +0000
  Re: Compiling and linking code from different places in the file system bartc <bc@freeuk.com> - 2018-03-01 14:55 +0000
    Re: Compiling and linking code from different places in the file system James Harris <james.harris.1@gmail.com> - 2018-03-02 21:05 +0000
      Re: Compiling and linking code from different places in the file system bartc <bc@freeuk.com> - 2018-03-03 01:18 +0000
        Re: Compiling and linking code from different places in the file system James Harris <james.harris.1@gmail.com> - 2018-03-09 01:03 +0000
      Re: Compiling and linking code from different places in the file system Rod Pemberton <NoEmail@trraxvfeqa.prg> - 2018-03-06 06:40 -0500
        Re: Compiling and linking code from different places in the file system James Harris <james.harris.1@gmail.com> - 2018-03-06 21:10 +0000
          Re: Compiling and linking code from different places in the file system Rod Pemberton <NoEmail@trraxvfeqa.prg> - 2018-03-07 06:58 -0500
            Re: Compiling and linking code from different places in the file system James Harris <james.harris.1@gmail.com> - 2018-03-09 01:23 +0000
              Re: Compiling and linking code from different places in the file system Rod Pemberton <NoEmail@trraxvfeqa.prg> - 2018-03-09 02:28 -0500
                Re: Compiling and linking code from different places in the file system Rod Pemberton <NoEmail@trraxvfeqa.prg> - 2018-03-09 02:44 -0500
                Re: Compiling and linking code from different places in the file system James Harris <james.harris.1@gmail.com> - 2018-03-09 23:26 +0000
                Re: Compiling and linking code from different places in the file system Rod Pemberton <NoEmail@trraxvfeqa.prg> - 2018-03-11 07:44 -0400
                Re: Compiling and linking code from different places in the file system James Harris <james.harris.1@gmail.com> - 2018-03-12 21:59 +0000
                Re: Compiling and linking code from different places in the file system Rod Pemberton <NoEmail@trraxvfeqa.prg> - 2018-03-14 01:45 -0400
                Re: Compiling and linking code from different places in the file system James Harris <james.harris.1@gmail.com> - 2018-03-14 10:59 +0000
      Re: Compiling and linking code from different places in the file system Rod Pemberton <NoEmail@trraxvfeqa.prg> - 2018-03-06 06:40 -0500
        Re: Compiling and linking code from different places in the file system James Harris <james.harris.1@gmail.com> - 2018-03-06 21:20 +0000
          Re: Compiling and linking code from different places in the file system Rod Pemberton <NoEmail@trraxvfeqa.prg> - 2018-03-07 06:58 -0500
            Re: Compiling and linking code from different places in the file system James Harris <james.harris.1@gmail.com> - 2018-03-09 10:30 +0000
  Re: Compiling and linking code from different places in the file system "James R. Kuyper" <jameskuyper@verizon.net> - 2018-03-01 11:11 -0500
    Re: Compiling and linking code from different places in the file system "James R. Kuyper" <jameskuyper@verizon.net> - 2018-03-01 13:51 -0500
    Re: Compiling and linking code from different places in the file system James Harris <james.harris.1@gmail.com> - 2018-03-03 09:48 +0000
  Re: Compiling and linking code from different places in the file system James Harris <james.harris.1@gmail.com> - 2018-03-03 12:25 +0000
    Re: Compiling and linking code from different places in the file system bartc <bc@freeuk.com> - 2018-03-03 15:32 +0000
      Re: Compiling and linking code from different places in the file system Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-03-04 07:52 +0000
      Re: Compiling and linking code from different places in the file system James Harris <james.harris.1@gmail.com> - 2018-03-04 08:43 +0000
        Re: Compiling and linking code from different places in the file system Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-03-05 07:58 +0000
          Re: Compiling and linking code from different places in the file system James Harris <james.harris.1@gmail.com> - 2018-03-06 21:37 +0000
            Re: Compiling and linking code from different places in the file system Jorgen Grahn <grahn+nntp@snipabacken.se> - 2018-03-07 21:02 +0000
        Re: Compiling and linking code from different places in the file system bartc <bc@freeuk.com> - 2018-03-05 15:29 +0000
          Re: Compiling and linking code from different places in the file system rugxulo@gmail.com - 2018-03-06 18:23 -0800
          Re: Compiling and linking code from different places in the file system James Harris <james.harris.1@gmail.com> - 2018-03-07 04:54 +0000
            Re: Compiling and linking code from different places in the file system Robert Wessel <robertwessel2@yahoo.com> - 2018-03-07 00:33 -0600
              Re: Compiling and linking code from different places in the file system James Harris <james.harris.1@gmail.com> - 2018-03-07 09:55 +0000
              Re: Compiling and linking code from different places in the file system bartc <bc@freeuk.com> - 2018-03-07 17:29 +0000
  Re: Compiling and linking code from different places in the file system Rod Pemberton <NoEmail@trraxvfeqa.prg> - 2018-03-06 06:39 -0500
    Re: Compiling and linking code from different places in the file system James Harris <james.harris.1@gmail.com> - 2018-03-07 10:44 +0000
      Re: Compiling and linking code from different places in the file system Rod Pemberton <NoEmail@trraxvfeqa.prg> - 2018-03-07 06:57 -0500
        Re: Compiling and linking code from different places in the file system James Harris <james.harris.1@gmail.com> - 2018-03-09 10:28 +0000
          Re: Compiling and linking code from different places in the file system Rod Pemberton <NoEmail@trraxvfeqa.prg> - 2018-03-11 07:44 -0400
            Re: Compiling and linking code from different places in the file system James Harris <james.harris.1@gmail.com> - 2018-03-12 22:44 +0000
              Re: Compiling and linking code from different places in the file system Rod Pemberton <NoEmail@trraxvfeqa.prg> - 2018-03-14 01:47 -0400
                Re: Compiling and linking code from different places in the file system bartc <bc@freeuk.com> - 2018-03-14 10:23 +0000
                Re: Compiling and linking code from different places in the file system "Pascal J. Bourguignon" <pjb@informatimago.com> - 2018-03-14 11:30 +0100
                Re: Compiling and linking code from different places in the file system bartc <bc@freeuk.com> - 2018-03-14 11:30 +0000
                Re: Compiling and linking code from different places in the file system "Pascal J. Bourguignon" <pjb@informatimago.com> - 2018-03-14 13:30 +0100
                Re: Compiling and linking code from different places in the file system bartc <bc@freeuk.com> - 2018-03-14 14:32 +0000
                Re: Compiling and linking code from different places in the file system "Pascal J. Bourguignon" <pjb@informatimago.com> - 2018-03-14 16:01 +0100
                Re: Compiling and linking code from different places in the file system bartc <bc@freeuk.com> - 2018-03-14 19:28 +0000
                Re: Compiling and linking code from different places in the file system "Pascal J. Bourguignon" <pjb@informatimago.com> - 2018-03-15 08:59 +0100
                Re: Compiling and linking code from different places in the file system bartc <bc@freeuk.com> - 2018-03-15 19:21 +0000
                Re: Compiling and linking code from different places in the file system "Pascal J. Bourguignon" <pjb@informatimago.com> - 2018-03-16 08:08 +0100
                Re: Compiling and linking code from different places in the file system bartc <bc@freeuk.com> - 2018-03-16 11:12 +0000
                Re: Compiling and linking code from different places in the file system "Pascal J. Bourguignon" <pjb@informatimago.com> - 2018-03-16 16:45 +0100
                Re: Compiling and linking code from different places in the file system Andy Walker <anw@cuboid.co.uk> - 2018-03-16 16:09 +0000
                Re: Compiling and linking code from different places in the file system "Pascal J. Bourguignon" <pjb@informatimago.com> - 2018-03-16 18:42 +0100
                Re: Compiling and linking code from different places in the file system bartc <bc@freeuk.com> - 2018-03-17 18:32 +0000
                Re: Compiling and linking code from different places in the file system "Pascal J. Bourguignon" <pjb@informatimago.com> - 2018-03-17 21:37 +0100
                Re: Compiling and linking code from different places in the file system bartc <bc@freeuk.com> - 2018-03-17 21:00 +0000
                Re: Compiling and linking code from different places in the file system "Pascal J. Bourguignon" <pjb@informatimago.com> - 2018-03-18 11:39 +0100
                Re: Compiling and linking code from different places in the file system bartc <bc@freeuk.com> - 2018-03-18 12:29 +0000
                Re: Compiling and linking code from different places in the file system Andy Walker <anw@cuboid.co.uk> - 2018-03-19 13:38 +0000
                Re: Compiling and linking code from different places in the file system James Harris <james.harris.1@gmail.com> - 2018-03-20 05:40 +0000
                Re: Compiling and linking code from different places in the file system Andy Walker <anw@cuboid.co.uk> - 2018-03-20 11:05 +0000
                Re: Compiling and linking code from different places in the file system James Harris <james.harris.1@gmail.com> - 2018-03-21 06:03 +0000
                Re: Compiling and linking code from different places in the file system Andy Walker <anw@cuboid.co.uk> - 2018-03-21 18:51 +0000
                Re: Compiling and linking code from different places in the file system James Harris <james.harris.1@gmail.com> - 2018-03-21 19:55 +0000
                Re: Compiling and linking code from different places in the file system Andy Walker <anw@cuboid.co.uk> - 2018-03-23 18:03 +0000
                Re: Compiling and linking code from different places in the file system James Harris <james.harris.1@gmail.com> - 2018-03-23 20:13 +0000
                Re: Compiling and linking code from different places in the file system Andy Walker <anw@cuboid.co.uk> - 2018-03-24 01:30 +0000
                Re: Compiling and linking code from different places in the file system James Harris <james.harris.1@gmail.com> - 2018-03-24 16:48 +0000
                Re: Compiling and linking code from different places in the file system Andy Walker <anw@cuboid.co.uk> - 2018-03-26 19:42 +0100
                Re: Compiling and linking code from different places in the file system James Harris <james.harris.1@gmail.com> - 2018-03-26 22:35 +0100
                Re: Compiling and linking code from different places in the file system "Pascal J. Bourguignon" <pjb@informatimago.com> - 2018-03-24 12:01 +0100
                Re: Compiling and linking code from different places in the file system "Pascal J. Bourguignon" <pjb@informatimago.com> - 2018-03-23 20:58 +0100
                Re: Compiling and linking code from different places in the file system "Pascal J. Bourguignon" <pjb@informatimago.com> - 2018-03-23 20:49 +0100
                Re: Compiling and linking code from different places in the file system bartc <bc@freeuk.com> - 2018-03-20 18:37 +0000
                Re: Compiling and linking code from different places in the file system Andy Walker <anw@cuboid.co.uk> - 2018-03-21 19:33 +0000
                Re: Compiling and linking code from different places in the file system bartc <bc@freeuk.com> - 2018-03-21 20:35 +0000
                Re: Compiling and linking code from different places in the file system "Pascal J. Bourguignon" <pjb@informatimago.com> - 2018-03-23 21:10 +0100
                Re: Compiling and linking code from different places in the file system Marco van de Voort <marcov@toad.stack.nl> - 2018-04-19 06:47 +0000
                Re: Compiling and linking code from different places in the file system Andy Walker <anw@cuboid.co.uk> - 2018-03-27 00:58 +0100
                Re: Compiling and linking code from different places in the file system bartc <bc@freeuk.com> - 2018-03-30 19:55 +0100
                Re: Compiling and linking code from different places in the file system Marco van de Voort <marcov@toad.stack.nl> - 2018-04-19 06:49 +0000
                Re: Compiling and linking code from different places in the file system "Pascal J. Bourguignon" <pjb@informatimago.com> - 2018-03-23 21:04 +0100
                Re: Compiling and linking code from different places in the file system bartc <bc@freeuk.com> - 2018-03-23 21:54 +0000
                Re: Compiling and linking code from different places in the file system "Pascal J. Bourguignon" <pjb@informatimago.com> - 2018-03-24 11:22 +0100
                Re: Compiling and linking code from different places in the file system bartc <bc@freeuk.com> - 2018-03-24 12:12 +0000
                Re: Compiling and linking code from different places in the file system "Pascal J. Bourguignon" <pjb@informatimago.com> - 2018-03-24 13:15 +0100
                Re: Compiling and linking code from different places in the file system "Pascal J. Bourguignon" <pjb@informatimago.com> - 2018-03-24 13:36 +0100
                Re: Compiling and linking code from different places in the file system bartc <bc@freeuk.com> - 2018-03-24 14:52 +0000
                Re: Compiling and linking code from different places in the file system Marco van de Voort <marcov@toad.stack.nl> - 2018-04-19 11:06 +0000
                Re: Compiling and linking code from different places in the file system David Brown <david.brown@hesbynett.no> - 2018-03-14 16:52 +0100
                Re: Compiling and linking code from different places in the file system bartc <bc@freeuk.com> - 2018-03-14 19:38 +0000
                Re: Compiling and linking code from different places in the file system "Pascal J. Bourguignon" <pjb@informatimago.com> - 2018-03-15 09:00 +0100
                Re: Compiling and linking code from different places in the file system bartc <bc@freeuk.com> - 2018-03-15 12:54 +0000
                Re: Compiling and linking code from different places in the file system James Harris <james.harris.1@gmail.com> - 2018-03-14 11:18 +0000
                Re: Compiling and linking code from different places in the file system "Pascal J. Bourguignon" <pjb@informatimago.com> - 2018-03-14 13:52 +0100
                Re: Compiling and linking code from different places in the file system Rod Pemberton <NoEmail@trraxvfeqa.prg> - 2018-03-15 06:29 -0400
                Re: Compiling and linking code from different places in the file system James Harris <james.harris.1@gmail.com> - 2018-03-15 20:37 +0000
                Re: Compiling and linking code from different places in the file system Rod Pemberton <NoEmail@trraxvfeqa.prg> - 2018-03-17 11:51 -0400
                Re: Compiling and linking code from different places in the file system James Harris <james.harris.1@gmail.com> - 2018-03-20 06:31 +0000
                Re: Compiling and linking code from different places in the file system Rod Pemberton <NoEmail@trraxvfeqa.prg> - 2018-03-20 17:14 -0400
                Re: Compiling and linking code from different places in the file system James Harris <james.harris.1@gmail.com> - 2018-03-21 07:10 +0000
                Re: Compiling and linking code from different places in the file system Rod Pemberton <NoEmail@trraxvfeqa.prg> - 2018-03-24 01:38 -0400
                Re: Compiling and linking code from different places in the file system James Harris <james.harris.1@gmail.com> - 2018-03-24 16:10 +0000
                Re: Compiling and linking code from different places in the file system Rod Pemberton <NoEmail@trraxvfeqa.prg> - 2018-03-24 20:05 -0400
                Re: Compiling and linking code from different places in the file system James Harris <james.harris.1@gmail.com> - 2018-03-25 16:55 +0100
  Re: Compiling and linking code from different places in the file system "Pascal J. Bourguignon" <pjb@informatimago.com> - 2018-03-14 13:39 +0100

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