Clean up "extern" declarations at the top of C files about cfe HOT 13 CLOSED

Imported from trac issue 8. Created by jphickey on 2014-12-30T19:34:31, last modified: 2019-03-05T14:57:55

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Trac comment by jphickey on 2015-01-26 14:00:03:

Pushed branch "trac-8-extern_decl_cleanups" to address this

Commit [changeset:62ec03db]

Ensure that all functions/variables that are referenced from a ".c" file other than the file containing the implementation/instantiation are properly prototyped in a header file.

The following rule was used to determine where the prototype/declaration should reside:

• For symbols that are only referenced within the same core app (e.g. ES calling another function within ES), place the declaration in a header file within the same core app. This also applies to symbols referenced from the unit test of the same app.
• For symbols that are referenced by other CFE core applications but not outside CFE core, place the declaration in a newly introduced "private" directory under the existing "inc" directory. Note that placing it here rather than in a separate directory such as "private_inc" allows the existing makefiles to find the new files without modifying include search paths.
• For symbols that are referenced outside CFE core, place the declaration in the public "inc" directory under the corresponding module.

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Trac comment by jphickey on 2015-01-26 14:05:13:

Important note regarding merging of the basic fix above:

An additional branch "merge-8+1-cmake_plus_refactor" is also pushed to reflect the merge between this fix and trac #32 (new build/cmake files).

Commit [changeset:ddecc89b]

This basically removes some extra items that had been required to make the build work without the trac 8 change in place. They become unnecessary after trac 8 is merged in.

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Trac comment by glimes on 2015-02-11 11:50:53:

Current version is [changeset:642acb9] plus [changeset:ddecc89b] merged in [changeset:e7a6636]

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Trac comment by jphickey on 2015-04-06 11:17:06:

This is ready for review/merge

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Trac comment by acudmore on 2015-04-06 14:24:18:

I think the reasoning is good, recommend accept.

Do you think anyone will confuse the inc/private files with the subsystem private headers? ( cfe_sb_priv.h? )

Could the private files implemented with a name and excluded from apps using a #ifdef guard?
( keeping them more consistent with the cfe_*_priv.h files )

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Trac comment by jphickey on 2015-04-06 14:37:29:

With respect to an #ifdef guard --

Actually my original version of this fix had this, the make script would define the CFE_CORE macro when compiling the core apps, and the private include files started in an #ifndef that would error out if someone tried to include them from somewhere else.

The only problem with this approach is that it broke the non-CMake build using the old makefiles, as these did not define the CFE_CORE macro. However they could probably be fixed to do so.

The other option is to put these into a directory at the same level as the "inc" (such as "private_inc") but this also requires a fix to both sets of makefiles to add another -I to the compiler command, and I think there are too many of these already.

At the end of the day I decided it was best to just leave well enough alone. With the way it is now, if someone includes this in an app they actually have to write {{{ #include "private/something.h" }}} which should set off some red flags that this is possibly a bad idea. If the code happens to work anyway, then that is OK, but they will be using it "at their own risk"....

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Trac comment by jwilmot on 2015-04-06 15:12:34:

Concur. Need to apply this solution to SBN which needs private headers.

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Trac comment by glimes on 2015-04-07 12:50:15:

Tested changesets [changeset:642acb9] [changeset:ddecc89] [changeset:e7a6636] as part of the ic-2015-03-10 merge.

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Trac comment by glimes on 2015-04-07 13:46:01:

Will retain these changesets in the merge; a new trac ticket will be opened
to track any further incremental improvemtns.

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Trac comment by glimes on 2015-04-13 15:13:24:

Part of integration candidate 2015-03-10,
committed to cFS CFE Development branch on 2015-04-10
as part of merge [changeset:7d6f6d0].

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Trac comment by glimes on 2016-02-16 13:16:45:

Susie confirmed these tickets have been approved for CFE 6.5

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Trac comment by jhageman on 2019-03-05 14:57:55:

Milestone renamed

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