On 10/13/25 15:53, Daniel Kiper wrote:
On Thu, Oct 09, 2025 at 03:18:34PM +0800, Michael Chang via Grub-devel wrote:
Add support for the 'z' length modifier in the printf code. This allows
printing of size_t and ssize_t values using %zu, %zd and related
formats. The parser maps 'z' to the correct integer width based on
sizeof (size_t).
Signed-off-by: Michael Chang <[email protected]>
---
grub-core/kern/misc.c | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/grub-core/kern/misc.c b/grub-core/kern/misc.c
index 2b7922393..ff614add5 100644
--- a/grub-core/kern/misc.c
+++ b/grub-core/kern/misc.c
@@ -26,6 +26,7 @@
#include <grub/i18n.h>
#include <grub/types.h>
#include <grub/charset.h>
+#include <stddef.h>
union printf_arg
{
@@ -739,6 +740,9 @@ parse_printf_arg_fmt (const char *fmt0, struct printf_args
*args,
COMPILE_TIME_ASSERT (sizeof (long) <= sizeof (long long));
COMPILE_TIME_ASSERT (sizeof (long long) == sizeof (void *)
|| sizeof (int) == sizeof (void *));
+ COMPILE_TIME_ASSERT (sizeof (size_t) == sizeof (unsigned)
+ || sizeof (size_t) == sizeof (unsigned long)
+ || sizeof (size_t) == sizeof (unsigned long long));
fmt = fmt0;
while ((c = *fmt++) != 0)
@@ -773,11 +777,17 @@ parse_printf_arg_fmt (const char *fmt0, struct
printf_args *args,
fmt++;
c = *fmt++;
+ if (c == 'z')
+ {
+ c = *fmt++;
+ goto do_count;
+ }
if (c == 'l')
c = *fmt++;
if (c == 'l')
c = *fmt++;
+ do_count:
switch (c)
{
case 'p':
@@ -874,6 +884,14 @@ parse_printf_arg_fmt (const char *fmt0, struct printf_args
*args,
continue;
}
+ if (c == 'z')
+ {
+ c = *fmt++;
+ if (sizeof (size_t) == sizeof (unsigned long))
This...
+ longfmt = 1;
+ else if (sizeof (size_t) == sizeof (unsigned long long))
... and this should be build time check...
Hello Daniel,
The compiler will evaluate the current ifs at build time if you don't
build with O0.
Do you prefer using #if to if?
Other projects go the opposite way. In U-Boot we try to replace #if by
if where possible to ensure that even if a build time check is made the
code in the unused branch is syntax checked.
Best regards
Heinrich
+ longfmt = 2;
+ }
Daniel
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