[LTP] asm-generic/int-ll64.h wrongly used on x86_64?

Cyril Hrubis chrubis@suse.cz
Fri Nov 19 13:38:06 CET 2021


Hi!
I was writing simple userspace code that prints the values from the
struct statx the line in question looks like:

	printf("%" PRIu64 "\n", st.stx_size);

This unexpectedly gives me warning on x86_64:

warning: format '%lu' expects argument of type 'long unsigned int', but argument 5 has type '__u64' {aka 'long long unsigned int'}

Digging into the issue I've found that include/asm-generic/types.h looks like:

#ifndef _ASM_GENERIC_TYPES_H
#define _ASM_GENERIC_TYPES_H
/*
 * int-ll64 is used everywhere now.
 */
#include <asm-generic/int-ll64.h>

#endif /* _ASM_GENERIC_TYPES_H */

Which is the cause why you cannot print __u64 with PRIu64 and would
force every userspace code to explicitly cast any __u64 in order to get
rid warnings. I would say that it would be better to fix the headers so
that __u64 has the same type as uint64_t so that PRIu64 could be then
used to print __u64 as well.

-- 
Cyril Hrubis
chrubis@suse.cz


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