system/uorb: Select the printf extension the format strings need. - #3792
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xiaoxiang781216 merged 1 commit intoSep 20, 2026
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Every topic's format string is printed through orb_info() or orb_fprintf(), and both reach the data through "%pB", which is a NuttX extension rather than a standard conversion. UORB_FORMAT turns that code on without turning the extension on, so a configuration that enables the listener but not the debug output builds cleanly, runs, and prints a pointer where the reading should be: sensor_voltage(now:4294968998000):0xc0203c98B The address is the va_format the extension was supposed to expand, and the trailing B is the conversion character being taken as ordinary text. Nothing warns, because to the compiler and to printf this is a valid format string that means something else. DEBUG_UORB already selects the extension, so the fault is invisible to anyone who turned that on. The two are independent options and only one of them declared what it needed. Move the select onto UORB_FORMAT, which is the option that decides whether the format strings are compiled in at all. Signed-off-by: Justin Hammond <justin@dynam.ac>
cederom
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Thank you @Fishwaldo :-)
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xiaoxiang781216
September 20, 2026 11:27
acassis
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Shouldn't we use "depends on"? |
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Summary
UORB_FORMATcompiles in the per-topic format strings, which reach their data through%pB. That is a NuttX printf extension, not a standard conversion, andUORB_FORMATdoes not select it.A configuration that enables the listener but not the debug output therefore builds cleanly, runs, and prints the pointer instead of the reading:
The address is the
va_formatthe extension was meant to expand, and the trailingBis the conversion character being taken as ordinary text. Nothing warns, because to the compiler and to printf this is a valid format string that means something else.DEBUG_UORBalready selects the extension, so the fault is invisible to anyone who has that on. The two are independent options and only one of them declared what it needed. Move theselectontoUORB_FORMAT, the option that decides whether the format strings exist at all.Impact
One line of
system/uorb/Kconfig. Affects configurations withUORB_FORMAT=yandDEBUG_UORB=n, which gainLIBC_PRINT_EXTENSION. Configurations that already setDEBUG_UORBare unchanged, since it selects the extension today.Testing
Reproduced on an ESWIN EIC7700 EVB with
UORB_FORMAT=yandDEBUG_UORB=n:uorb_listenerprinted0xc0203c98Bfor every sample. With this change the same build prints the value: