[BUILD] Fail early if findsymbols fails #446
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If `findsymbols` fails, it prints a helpful usage message to standard output: > Usage: findsymbols file [-p prefix] symbol ... > file: > Symbol file created with the -Ln option in ld65 > -p prefix: > A prefix added to all returned symbol names > symbol: > Name of one or more symbols Unfortunately, the Makefile ignores the exit status of `findsymbols`. It then misinterprets the whole help text as legitimate output and rolls it all into the linker command line. Because the help text happens to contain the word `-Ln` and there’s another `-Ln` in the command line already, so the linker treats this duplication as an error and bails: > ld65: Error: Cannot use -Ln twice which was also reported in GitHub issue X16Community#363 [1]. To improve the error message and fix the leaky help text: 1. Add a conditional block that queries `.SHELLSTATUS`, a variable which was introduced in GNU Make v4.2, and if it is nonzero, error out early with the message "findsymbols failed with exit code $(.SHELLSTATUS)." 2. Additionally, improve `findsymbols` so it redirects the usage text to standard error and includes the file name in its "File not found" message. That way, the message can be seen by the user who ran `make`. It can also no longer be mistaken for machine-readable output. Example output of `make`: > File not found: build/x16/dos.sym > Usage: findsymbols file [-p prefix] symbol ... > file: > Symbol file created with the -Ln option in ld65 > -p prefix: > A prefix added to all returned symbol names > symbol: > Name of one or more symbols > Makefile:407: *** findsymbols failed with exit code 1. Stop. 3. To avoid peppering the whole Makefile with exit code guards, declare a `findsymbols` function that hides the complexity. 4. As an unwanted side effect, calling a function causes Make to misinterpret the `$` address prefixes that occur in the `findsymbols` output. To counteract that, escape every `$` with `$$`. 5. As a graceful fallback for users of GNU Make versions older than 4.2, default `.SHELLSTATUS` to 0. In that case, we have no early returns, but users still get a somewhat meaningful error message that says e.g., "Unresolved external 'skip_mask' referenced in: fat32/match.s", which is still much more helpful than "ld65: Error: Cannot use -Ln twice". [1]: X16Community#363
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mooinglemur
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Dec 2, 2025
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Thanks! This definitely helps.
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If
findsymbolsfails, it prints a helpful usage message to standard output:Unfortunately, the Makefile ignores the exit status of
findsymbols. It then misinterprets the whole help text as legitimate output and rolls it all into the linker command line.Because the help text happens to contain the word
-Lnand there’s another-Lnin the command line already, the linker treats this duplication as an error and bails with the error message from issue #363:This PR is to improve the error message and fix the leaky help text.
It redirects the help text to stderr (so the help text is no longer misinterpreted as legitimate output) and adds an exit status guard (so the build fails early with a more useful error message.)
See my commit message for more details.
Note that this PR does not fix the root cause of #363, which I think should be a separate PR.
@mooinglemur Review would be appreciated.