[PATCH v5 next 09/17] tools/nolibc/printf: Add support for length modifiers tzqL and formats iX
From: david . laight . linux
Date: Sun Mar 08 2026 - 07:39:06 EST
From: David Laight <david.laight.linux@xxxxxxxxx>
Length modifiers t (ptrdiff_t) and z (size_t) are aliases for l (long),
q and L are 64bit the same as j (intmax).
Format i is an alias for d and X similar to x but uppper case.
Supporting them is mostly just adding the relavant bit to the bit
pattern used for maching characters.
Although %X is detected the output will be lower case.
Change/add tests to use conversions i and X, and length modifiers L and ll.
Use the correct minimum value for "%Li".
Acked-by: Willy Tarreau <w@xxxxxx>
Signed-off-by: David Laight <david.laight.linux@xxxxxxxxx>
---
Unchanged for v5.
v4: Split from the previous patch.
tools/include/nolibc/stdio.h | 27 ++++++++++++--------
tools/testing/selftests/nolibc/nolibc-test.c | 14 +++++++---
2 files changed, 27 insertions(+), 14 deletions(-)
diff --git a/tools/include/nolibc/stdio.h b/tools/include/nolibc/stdio.h
index 1c2b2cf9a1f3..09ea2e0c392f 100644
--- a/tools/include/nolibc/stdio.h
+++ b/tools/include/nolibc/stdio.h
@@ -291,10 +291,11 @@ int fseek(FILE *stream, long offset, int whence)
}
-/* printf(). Supports the following integer and string formats.
- * - %[#-+ 0][width][{l,ll,j}]{c,d,u,x,p,s,m,%}
+/* printf(). Supports most of the normal integer and string formats.
+ * - %[#-+ 0][width][{l,t,z,ll,L,j,q}]{c,d,i,u,x,X,p,s,m,%}
* - %% generates a single %
* - %m outputs strerror(errno).
+ * - %X outputs a..f the same as %x.
* - The modifiers [#-+ 0] are currently ignored.
* - No support for precision or variable widths.
* - No support for floating point or wide characters.
@@ -386,9 +387,11 @@ int __nolibc_printf(__nolibc_printf_cb cb, void *state, const char *fmt, va_list
/* Length modifier.
* They miss the conversion flags characters " #+-0" so can go into flags.
- * Change ll to j (both always 64bits).
+ * Change both L and ll to j (all alwys 64bit).
*/
- ch_flag = _NOLIBC_PF_CHAR_IS_ONE_OF(ch, 'l', 'j');
+ if (ch == 'L')
+ ch = 'j';
+ ch_flag = _NOLIBC_PF_CHAR_IS_ONE_OF(ch, 'l', 't', 'z', 'j', 'q');
if (ch_flag != 0) {
if (ch == 'l' && fmt[0] == 'l') {
fmt++;
@@ -403,20 +406,22 @@ int __nolibc_printf(__nolibc_printf_cb cb, void *state, const char *fmt, va_list
/* Numeric and pointer conversion specifiers.
*
* Use an explicit bound check (rather than _NOLIBC_PF_CHAR_IS_ONE_OF())
- * so ch_flag can be used later.
+ * so that 'X' can be allowed through.
+ * 'X' gets treated and 'x' because _NOLIBC_PF_FLAG() returns the same
+ * value for both.
*/
ch_flag = _NOLIBC_PF_FLAG(ch);
- if ((ch >= 'a' && ch <= 'z') &&
- _NOLIBC_PF_FLAGS_CONTAIN(ch_flag, 'c', 'd', 'u', 'x', 'p')) {
+ if (((ch >= 'a' && ch <= 'z') || ch == 'X') &&
+ _NOLIBC_PF_FLAGS_CONTAIN(ch_flag, 'c', 'd', 'i', 'u', 'x', 'p')) {
/* 'long' is needed for pointer conversions and ltz lengths.
* A single test can be used provided 'p' (the same bit as '0')
* is masked from flags.
*/
if (_NOLIBC_PF_FLAGS_CONTAIN(ch_flag | (flags & ~_NOLIBC_PF_FLAG('p')),
- 'p', 'l')) {
+ 'p', 'l', 't', 'z')) {
v = va_arg(args, unsigned long);
signed_v = (long)v;
- } else if (_NOLIBC_PF_FLAGS_CONTAIN(flags, 'j')) {
+ } else if (_NOLIBC_PF_FLAGS_CONTAIN(flags, 'j', 'q')) {
v = va_arg(args, unsigned long long);
signed_v = v;
} else {
@@ -434,7 +439,7 @@ int __nolibc_printf(__nolibc_printf_cb cb, void *state, const char *fmt, va_list
out = outbuf;
- if (_NOLIBC_PF_FLAGS_CONTAIN(ch_flag, 'd')) {
+ if (_NOLIBC_PF_FLAGS_CONTAIN(ch_flag, 'd', 'i')) {
/* "%d" and "%i" - signed decimal numbers. */
if (signed_v < 0) {
*out++ = '-';
@@ -444,7 +449,7 @@ int __nolibc_printf(__nolibc_printf_cb cb, void *state, const char *fmt, va_list
}
/* Convert the number to ascii in the required base. */
- if (_NOLIBC_PF_FLAGS_CONTAIN(ch_flag, 'd', 'u')) {
+ if (_NOLIBC_PF_FLAGS_CONTAIN(ch_flag, 'd', 'i', 'u')) {
/* Base 10 */
u64toa_r(v, out);
} else {
diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c
index 638f18fc5123..a140c54e4d72 100644
--- a/tools/testing/selftests/nolibc/nolibc-test.c
+++ b/tools/testing/selftests/nolibc/nolibc-test.c
@@ -1826,11 +1826,19 @@ static int run_printf(int min, int max)
CASE_TEST(number); EXPECT_VFPRINTF(1, "1234", "%d", 1234); break;
CASE_TEST(negnumber); EXPECT_VFPRINTF(1, "-1234", "%d", -1234); break;
CASE_TEST(unsigned); EXPECT_VFPRINTF(1, "12345", "%u", 12345); break;
+ CASE_TEST(signed_max); EXPECT_VFPRINTF(1, "2147483647", "%i", ~0u >> 1); break;
+ CASE_TEST(signed_min); EXPECT_VFPRINTF(1, "-2147483648", "%i", (~0u >> 1) + 1); break;
+ CASE_TEST(unsigned_max); EXPECT_VFPRINTF(1, "4294967295", "%u", ~0u); break;
CASE_TEST(char); EXPECT_VFPRINTF(1, "c", "%c", 'c'); break;
- CASE_TEST(hex); EXPECT_VFPRINTF(1, "f", "%x", 0xf); break;
+ CASE_TEST(hex_nolibc); EXPECT_VFPRINTF(is_nolibc, "|f|d|", "|%x|%X|", 0xf, 0xd); break;
+ CASE_TEST(hex_libc); EXPECT_VFPRINTF(!is_nolibc, "|f|D|", "|%x|%X|", 0xf, 0xd); break;
CASE_TEST(pointer); EXPECT_VFPRINTF(1, "0x1", "%p", (void *) 0x1); break;
- CASE_TEST(uintmax_t); EXPECT_VFPRINTF(1, "18446744073709551615", "%ju", 0xffffffffffffffffULL); break;
- CASE_TEST(intmax_t); EXPECT_VFPRINTF(1, "-9223372036854775807", "%jd", 0x8000000000000001LL); break;
+ CASE_TEST(percent); EXPECT_VFPRINTF(1, "a%d42%69%", "a%%d%d%%%d%%", 42, 69); break;
+ CASE_TEST(perc_qual); EXPECT_VFPRINTF(1, "a%d2", "a%-14l%d%d", 2); break;
+ CASE_TEST(invalid); EXPECT_VFPRINTF(1, "a%12yx3%y42%P", "a%12yx%d%y%d%P", 3, 42); break;
+ CASE_TEST(intmax_max); EXPECT_VFPRINTF(1, "9223372036854775807", "%lld", ~0ULL >> 1); break;
+ CASE_TEST(intmax_min); EXPECT_VFPRINTF(1, "-9223372036854775808", "%Li", (~0ULL >> 1) + 1); break;
+ CASE_TEST(uintmax_max); EXPECT_VFPRINTF(1, "18446744073709551615", "%ju", ~0ULL); break;
CASE_TEST(truncation); EXPECT_VFPRINTF(1, "0123456789012345678901234", "%s", "0123456789012345678901234"); break;
CASE_TEST(string_width); EXPECT_VFPRINTF(1, " 1", "%10s", "1"); break;
CASE_TEST(number_width); EXPECT_VFPRINTF(1, " 1", "%10d", 1); break;
--
2.39.5