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apache / nuttx-apps

Apache NuttX Apps is a collection of tools, shells, network utilities, libraries, interpreters and can be used with the NuttX RTOS
https://nuttx.apache.org/
Apache License 2.0
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mutliple PROGNAME not working correctly #633

Closed protobits closed 1 year ago

protobits commented 3 years ago

An application Make.defs can define multiple builtin applications by using something like:

MAINCSRCS = a.c b.c
PROGNAME = a b

When building a.c the -Dmain=a_main will be defined, and similarly for b.c. However, the logic in Application.mk simply iterates PROGNAME in order to build each main definition. This assumes that all targets will be built. When only one of these is built (as part of a previous build), it will mismatch the corresponding program name (it will go in order from first PROGNAME entry).

The correct solution would be to find the index of the C file in MAINCSRCS and get the corresponding entry in PROGNAME. Make does not implement such a function and there's some trickery to do so: https://stackoverflow.com/questions/9674711/makefile-find-a-position-of-word-in-a-variable

As the Application.mk file is already really convoluted I don't want to keep making this worse.

Any better ideas?

This of course would be much easier if we just used the .c file name as PROGNAME but that would be a breaking change for apps using a different name.

protobits commented 3 years ago

This is the problematic line: https://github.com/apache/incubator-nuttx-apps/blob/f3828ccbca3e45319d804cd5c3f91a4764de68c8/Application.mk#L185

acassis commented 3 years ago

Good finding @v01d ! Is this multiple buitin applications feature documented in some place?

protobits commented 3 years ago

Not really, it would be good to have a section in the docs explaining how to write an app (maybe under "applications").

protobits commented 3 years ago

A workaround is to not use main to define the entry point, the <progname>_main and thus not rely on this feature.

acassis commented 3 years ago

Well, in the past it was appxyz_main(), move to main() was an improvement. Maybe we can fix it without returning to the previous way to do it.

protobits commented 3 years ago

I don't really have a better proposal and don't really like the added complexity of the solution, so I will just leave this issue open in case someone thinks of a better approach. I mentioned the workaround in case someone bumps into the problem. I wasn't proposing we adopt it for existing apps, since it would be going backwards as you mention.

normanr commented 2 years ago

Instead of finding the index of the string, you could zip the two lists together (https://riptutorial.com/makefile/example/23643/zipping-lists), and then eval a template (https://www.gnu.org/software/make/manual/html_node/Eval-Function.html) for each pair.

xiaoxiang781216 commented 2 years ago

Yes, this is the right approach to fix this problem I discussed internally with @anchao .

xuxin930 commented 1 year ago

Yes, this is the right approach to fix this problem I discussed internally with @anchao .

@anchao has fixed this incremental compilation issue in this excellent work https://github.com/apache/nuttx-apps/pull/1603, but there is also a potential risk:

[!IMPORTANT] If an application has MAINSRCS with the same name in different directories, function GETENTRYINDEX will have wrong results because notdir is used.

I plan to establish a mapping relationship between progname and src during defining variables.