ADA File Names vs. Package Names - ada

Question

I inherited an ADA program where the source file names and package file names don't follow the default naming convention. ADA is new to me, so I may be missing something simple, but I can't see it in the GNAT Pro User's Guide. (This similar question didn't help me.)
Here are a couple of examples:
File Name: C_Comm_Config_S.Ada
Package Name: Comm_Configuration
File Name: D_Bus_Buffers_S.Ada
Package Name: Bus_Buffers
I think I have the _S.Ada and _B.Ada sorted out, but I can't find anything in the program source or build files that show the binding between the Package Name and the rest of the File Name.
When I compile a file that doesn't use any other packages, I get a warning: file name does not match unit name... This appears to be from the prefix of C_ or D_, in this particular case.
Also, I'm not clear if the prefixes C_ and D_ have any special meaning in the context of ADA, but if it does, I'd like to know about it.
So I appear to have two issues, the Prefix of C_ or D_ and in some cases the rest of the file name doesn't match the package.

Answer 1

You could use gnatname: see the User’s Guide.
I copied subdirectories a/ and d/ from the ACATS test suite to a working directory and created a project file p.gpr:
project p is
for source_dirs use ("a", "d");
end p;
and ran gnatname with
gnatname -P p -d a -d d \*.ada
which resulted in an edited p.gpr and two new files, p_naming.gpr and p_source_list.txt. These are rather long, but look like
p.gpr:
with "p_naming.gpr";
project P is
for Source_List_File use "p_source_list.txt";
for Source_Dirs use ("a", "d");
package Naming renames P_Naming.Naming;
end P;
p_naming.gpr:
project P_Naming is
for Source_Files use ();
package Naming is
for Body ("d4a004b") use "d4a004b.ada";
for Body ("d4a004a") use "d4a004a.ada";
for Body ("d4a002b") use "d4a002b.ada";
...
for Body ("aa2010a_parent.boolean") use "aa2010a.ada" at 4;
for Body ("aa2010a_parent") use "aa2010a.ada" at 3;
for Spec ("aa2010a_parent") use "aa2010a.ada" at 2;
for Spec ("aa2010a_typedef") use "aa2010a.ada" at 1;
...
for Body ("a22006d") use "a22006d.ada";
for Body ("a22006c") use "a22006c.ada";
for Body ("a22006b") use "a22006b.ada”;
end Naming;
end P_Naming;
The for Body ("aa2010a_parent") use "aa2010a.ada" at 3; is used when there’s more than one unit in the source file.
p_source_list.txt:
a22006b.ada
a22006c.ada
a22006d.ada
a27003a.ada
a29003a.ada
...
d4a002b.ada
d4a004a.ada
d4a004b.ada
When building, for example, test d4a004b, you have to use the file name and suffix:
gnatmake -P p d4a004b.ada

Answer 2

The Ada standard does not say anything about source file naming conventions. As it appears that you use GNAT, I assume that you mean the "GNAT default naming convention".
You can tell GNAT about alternatively named files in a Naming package inside your project files.
A simple example:
project OpenID is
...
package Naming is
for Implementation ("Util.Log.Loggers.Traceback")
use "util-log-loggers-traceback-gnat.adb";
for Implementation ("Util.Serialize.IO.XML.Get_Location")
use "util-serialize-io-xml-get_location-xmlada-4.adb";
end Naming;
end OpenID;