Undeclared identifier compile error from Objective-C

[matthewrfennell]

Calling some functions, such as sqlite3_libversion(), from Objective-C causes the compile error "Use of undeclared identifier 'sqlite3_api'". See this minimal test. Swift code calling these functions compile fine.

As a workaround, #defineing either SQLITE_CORE or SQLITE_OMIT_LOAD_EXTENSIONS in sqlite3ext.h removes this error. This suggests that the SQLITE_CORE definition in Package.swift is somehow not being handled correctly when called through Objective-C.

I'll continue looking at this, but any ideas of how this is happening only in Objective-C or how to narrow down the investigation are appreciated.

[sbooth]

Does the behavior change if instead of importing the CSQLite module you include only sqlite3.h?

[matthewrfennell]

No change if I #import <sqlite3.h> or #import "sqlite3.h" (I presume they ultimately resolve via the modulemap anyway).

But, as a workaround, if I remove sqlite3ext.h from the modulemap, it compiles fine (apart from the swift tests that rely on extensions).

[sbooth]

I have two potential fixes for this, both to the module map:

module CSQLite {
	header "sqlite3.h"
	textual header "sqlite3ext.h"
	header "csqlite_shims.h"
	export *
}

or

module CSQLite {
	module csqlite {
		header "sqlite3.h"
		header "csqlite_shims.h"
	}

	explicit module ext {
		textual header "sqlite3ext.h"
	}

	export csqlite
}

At the end of the day they do essentially the same thing. I'm leaning toward the second version since it only makes sqlite3ext.h available if it is explicitly requested.

[matthewrfennell]

Both fix the error for me (both in the test, and the project where I initially triggered the compile error).

Thank you!

[sbooth]

Thank you for reporting this issue!