The implementation is limited and only supports numeric arguments.
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
---
tools/include/nolibc/stdio.h | 93 ++++++++++++++++++++++++++++
tools/testing/selftests/nolibc/nolibc-test.c | 59 ++++++++++++++++++
2 files changed, 152 insertions(+)
diff --git a/tools/include/nolibc/stdio.h b/tools/include/nolibc/stdio.h
index c968dbbc4ef8..d63c45c06d8e 100644
--- a/tools/include/nolibc/stdio.h
+++ b/tools/include/nolibc/stdio.h
@@ -348,6 +348,99 @@ int printf(const char *fmt, ...)
return ret;
}
+static __attribute__((unused))
+int vsscanf(const char *str, const char *format, va_list args)
+{
+ uintmax_t uval;
+ intmax_t ival;
+ int base;
+ char *endptr;
+ int matches;
+ int lpref;
+
+ matches = 0;
+
+ while (1) {
+ if (*format == '%') {
+ lpref = 0;
+ format++;
+
+ if (*format == 'l') {
+ lpref = 1;
+ format++;
+ if (*format == 'l') {
+ lpref = 2;
+ format++;
+ }
+ }
+
+ if (*format == '%') {
+ if ('%' != *str)
+ goto done;
+ str++;
+ format++;
+ continue;
+ } else if (*format == 'd') {
+ ival = strtoll(str, &endptr, 10);
+ if (lpref == 0)
+ *va_arg(args, int *) = ival;
+ else if (lpref == 1)
+ *va_arg(args, long *) = ival;
+ else if (lpref == 2)
+ *va_arg(args, long long *) = ival;
+ } else if (*format == 'u' || *format == 'x' || *format == 'X') {
+ base = *format == 'u' ? 10 : 16;
+ uval = strtoull(str, &endptr, base);
+ if (lpref == 0)
+ *va_arg(args, unsigned int *) = uval;
+ else if (lpref == 1)
+ *va_arg(args, unsigned long *) = uval;
+ else if (lpref == 2)
+ *va_arg(args, unsigned long long *) = uval;
+ } else if (*format == 'p') {
+ *va_arg(args, void **) = (void *)strtoul(str, &endptr, 16);
+ } else {
+ SET_ERRNO(EILSEQ);
+ goto done;
+ }
+
+ format++;
+ str = endptr;
+ matches++;
+
+ } else if (*format == '\0') {
+ goto done;
+ } else if (isspace(*format)) {
+ while (isspace(*format))
+ format++;
+ while (isspace(*str))
+ str++;
+ } else if (*format == *str) {
+ format++;
+ str++;
+ } else {
+ if (!matches)
+ matches = EOF;
+ goto done;
+ }
+ }
+
+done:
+ return matches;
+}
+
+static __attribute__((unused, format(scanf, 2, 3)))
+int sscanf(const char *str, const char *format, ...)
+{
+ va_list args;
+ int ret;
+
+ va_start(args, format);
+ ret = vsscanf(str, format, args);
+ va_end(args);
+ return ret;
+}
+
static __attribute__((unused))
void perror(const char *msg)
{
diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c
index 093d0512f4c5..addbceb0b276 100644
--- a/tools/testing/selftests/nolibc/nolibc-test.c
+++ b/tools/testing/selftests/nolibc/nolibc-test.c
@@ -1277,6 +1277,64 @@ static int expect_vfprintf(int llen, int c, const char *expected, const char *fm
return ret;
}
+static int test_scanf(void)
+{
+ unsigned long long ull;
+ unsigned long ul;
+ unsigned int u;
+ long long ll;
+ long l;
+ void *p;
+ int i;
+
+ if (sscanf("", "foo") != EOF)
+ return 1;
+
+ if (sscanf("foo", "foo") != 0)
+ return 2;
+
+ if (sscanf("123", "%d", &i) != 1)
+ return 3;
+
+ if (i != 123)
+ return 4;
+
+ if (sscanf("a123b456c0x90", "a%db%uc%p", &i, &u, &p) != 3)
+ return 5;
+
+ if (i != 123)
+ return 6;
+
+ if (u != 456)
+ return 7;
+
+ if (p != (void *)0x90)
+ return 8;
+
+ if (sscanf("a b1", "a b%d", &i) != 1)
+ return 9;
+
+ if (i != 1)
+ return 10;
+
+ if (sscanf("a%1", "a%%%d", &i) != 1)
+ return 11;
+
+ if (i != 1)
+ return 12;
+
+ if (sscanf("1|2|3|4|5|6",
+ "%d|%ld|%lld|%u|%lu|%llu",
+ &i, &l, &ll, &u, &ul, &ull) != 6)
+ return 13;
+
+ if (i != 1 || l != 2 || ll != 3 ||
+ u != 4 || ul != 5 || ull != 6)
+ return 14;
+
+ return 0;
+}
+
static int run_vfprintf(int min, int max)
{
int test;
@@ -1298,6 +1356,7 @@ static int run_vfprintf(int min, int max)
CASE_TEST(char); EXPECT_VFPRINTF(1, "c", "%c", 'c'); break;
CASE_TEST(hex); EXPECT_VFPRINTF(1, "f", "%x", 0xf); break;
CASE_TEST(pointer); EXPECT_VFPRINTF(3, "0x1", "%p", (void *) 0x1); break;
+ CASE_TEST(scanf); EXPECT_ZR(1, test_scanf()); break;
case __LINE__:
return ret; /* must be last */
/* note: do not set any defaults so as to permit holes above */
--
2.46.0
On 7/31/24 12:32, Thomas Weißschuh wrote:
> The implementation is limited and only supports numeric arguments.
I would like to see more information in here. Why is this needed
etc. etc.
>
> Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
> ---
> tools/include/nolibc/stdio.h | 93 ++++++++++++++++++++++++++++
> tools/testing/selftests/nolibc/nolibc-test.c | 59 ++++++++++++++++++
> 2 files changed, 152 insertions(+)
>
> diff --git a/tools/include/nolibc/stdio.h b/tools/include/nolibc/stdio.h
> index c968dbbc4ef8..d63c45c06d8e 100644
> --- a/tools/include/nolibc/stdio.h
> +++ b/tools/include/nolibc/stdio.h
> @@ -348,6 +348,99 @@ int printf(const char *fmt, ...)
> return ret;
> }
>
> +static __attribute__((unused))
> +int vsscanf(const char *str, const char *format, va_list args)
Is there a reason why you didn't use the same code in lib/vsprintf.c?
You could simply duplicate the code here?
With all these libc functionality added, it isn't nolibc looks like :)
> +{
> + uintmax_t uval;
> + intmax_t ival;
> + int base;
> + char *endptr;
> + int matches;
> + int lpref;
> +
> + matches = 0;
> +
> + while (1) {
> + if (*format == '%') {
> + lpref = 0;
> + format++;
> +
> + if (*format == 'l') {
> + lpref = 1;
> + format++;
> + if (*format == 'l') {
> + lpref = 2;
> + format++;
> + }
> + }
> +
> + if (*format == '%') {
> + if ('%' != *str)
> + goto done;
> + str++;
> + format++;
> + continue;
> + } else if (*format == 'd') {
> + ival = strtoll(str, &endptr, 10);
> + if (lpref == 0)
> + *va_arg(args, int *) = ival;
> + else if (lpref == 1)
> + *va_arg(args, long *) = ival;
> + else if (lpref == 2)
> + *va_arg(args, long long *) = ival;
> + } else if (*format == 'u' || *format == 'x' || *format == 'X') {
> + base = *format == 'u' ? 10 : 16;
> + uval = strtoull(str, &endptr, base);
> + if (lpref == 0)
> + *va_arg(args, unsigned int *) = uval;
> + else if (lpref == 1)
> + *va_arg(args, unsigned long *) = uval;
> + else if (lpref == 2)
> + *va_arg(args, unsigned long long *) = uval;
> + } else if (*format == 'p') {
> + *va_arg(args, void **) = (void *)strtoul(str, &endptr, 16);
> + } else {
> + SET_ERRNO(EILSEQ);
> + goto done;
> + }
> +
> + format++;
> + str = endptr;
> + matches++;
> +
> + } else if (*format == '\0') {
> + goto done;
> + } else if (isspace(*format)) {
> + while (isspace(*format))
> + format++;
> + while (isspace(*str))
> + str++;
> + } else if (*format == *str) {
> + format++;
> + str++;
> + } else {
> + if (!matches)
> + matches = EOF;
> + goto done;
> + }
> + }
> +
> +done:
> + return matches;
> +}
> +
> +static __attribute__((unused, format(scanf, 2, 3)))
> +int sscanf(const char *str, const char *format, ...)
> +{
> + va_list args;
> + int ret;
> +
> + va_start(args, format);
> + ret = vsscanf(str, format, args);
> + va_end(args);
> + return ret;
> +}
> +
> static __attribute__((unused))
> void perror(const char *msg)
> {
> diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c
> index 093d0512f4c5..addbceb0b276 100644
> --- a/tools/testing/selftests/nolibc/nolibc-test.c
> +++ b/tools/testing/selftests/nolibc/nolibc-test.c
> @@ -1277,6 +1277,64 @@ static int expect_vfprintf(int llen, int c, const char *expected, const char *fm
> return ret;
> }
>
> +static int test_scanf(void)
> +{
> + unsigned long long ull;
> + unsigned long ul;
> + unsigned int u;
> + long long ll;
> + long l;
> + void *p;
> + int i;
> +
> + if (sscanf("", "foo") != EOF)
> + return 1;
> +
> + if (sscanf("foo", "foo") != 0)
> + return 2;
> +
> + if (sscanf("123", "%d", &i) != 1)
> + return 3;
> +
> + if (i != 123)
> + return 4;
> +
> + if (sscanf("a123b456c0x90", "a%db%uc%p", &i, &u, &p) != 3)
> + return 5;
> +
> + if (i != 123)
> + return 6;
> +
> + if (u != 456)
> + return 7;
> +
> + if (p != (void *)0x90)
> + return 8;
> +
> + if (sscanf("a b1", "a b%d", &i) != 1)
> + return 9;
> +
> + if (i != 1)
> + return 10;
> +
> + if (sscanf("a%1", "a%%%d", &i) != 1)
> + return 11;
> +
> + if (i != 1)
> + return 12;
> +
> + if (sscanf("1|2|3|4|5|6",
> + "%d|%ld|%lld|%u|%lu|%llu",
> + &i, &l, &ll, &u, &ul, &ull) != 6)
> + return 13;
> +
> + if (i != 1 || l != 2 || ll != 3 ||
> + u != 4 || ul != 5 || ull != 6)
> + return 14;
> +
> + return 0;
Can we simplify this code? It is hard to read code with too
many conditions. Maybe defining an array test conditions
instead of a series ifs.
> +}
> +
> static int run_vfprintf(int min, int max)
> {
> int test;
> @@ -1298,6 +1356,7 @@ static int run_vfprintf(int min, int max)
> CASE_TEST(char); EXPECT_VFPRINTF(1, "c", "%c", 'c'); break;
> CASE_TEST(hex); EXPECT_VFPRINTF(1, "f", "%x", 0xf); break;
> CASE_TEST(pointer); EXPECT_VFPRINTF(3, "0x1", "%p", (void *) 0x1); break;
> + CASE_TEST(scanf); EXPECT_ZR(1, test_scanf()); break;
> case __LINE__:
> return ret; /* must be last */
> /* note: do not set any defaults so as to permit holes above */
>
thanks,
-- Shuah
On 2024-07-31 17:01:09+0000, Shuah Khan wrote:
> On 7/31/24 12:32, Thomas Weißschuh wrote:
> > The implementation is limited and only supports numeric arguments.
>
> I would like to see more information in here. Why is this needed
> etc. etc.
Ack.
> >
> > Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
> > ---
> > tools/include/nolibc/stdio.h | 93 ++++++++++++++++++++++++++++
> > tools/testing/selftests/nolibc/nolibc-test.c | 59 ++++++++++++++++++
> > 2 files changed, 152 insertions(+)
> >
> > diff --git a/tools/include/nolibc/stdio.h b/tools/include/nolibc/stdio.h
> > index c968dbbc4ef8..d63c45c06d8e 100644
> > --- a/tools/include/nolibc/stdio.h
> > +++ b/tools/include/nolibc/stdio.h
> > @@ -348,6 +348,99 @@ int printf(const char *fmt, ...)
> > return ret;
> > }
> > +static __attribute__((unused))
> > +int vsscanf(const char *str, const char *format, va_list args)
>
> Is there a reason why you didn't use the same code in lib/vsprintf.c?
> You could simply duplicate the code here?
lib/vsprintf.c is GPL-2.0-only while nolibc is LGPL-2.1 OR MIT,
so code reuse isn't really possible.
Furthermore I think the vsprintf.c implements the custom kernel formats,
while nolibc should use posix ones.
> With all these libc functionality added, it isn't nolibc looks like :)
Well :-)
The main motivation is to provide kselftests compatibility.
Maybe Willy disagrees.
> > +{
> > + uintmax_t uval;
> > + intmax_t ival;
> > + int base;
> > + char *endptr;
> > + int matches;
> > + int lpref;
> > +
> > + matches = 0;
> > +
> > + while (1) {
> > + if (*format == '%') {
> > + lpref = 0;
> > + format++;
> > +
> > + if (*format == 'l') {
> > + lpref = 1;
> > + format++;
> > + if (*format == 'l') {
> > + lpref = 2;
> > + format++;
> > + }
> > + }
> > +
> > + if (*format == '%') {
> > + if ('%' != *str)
> > + goto done;
> > + str++;
> > + format++;
> > + continue;
> > + } else if (*format == 'd') {
> > + ival = strtoll(str, &endptr, 10);
> > + if (lpref == 0)
> > + *va_arg(args, int *) = ival;
> > + else if (lpref == 1)
> > + *va_arg(args, long *) = ival;
> > + else if (lpref == 2)
> > + *va_arg(args, long long *) = ival;
> > + } else if (*format == 'u' || *format == 'x' || *format == 'X') {
> > + base = *format == 'u' ? 10 : 16;
> > + uval = strtoull(str, &endptr, base);
> > + if (lpref == 0)
> > + *va_arg(args, unsigned int *) = uval;
> > + else if (lpref == 1)
> > + *va_arg(args, unsigned long *) = uval;
> > + else if (lpref == 2)
> > + *va_arg(args, unsigned long long *) = uval;
> > + } else if (*format == 'p') {
> > + *va_arg(args, void **) = (void *)strtoul(str, &endptr, 16);
> > + } else {
> > + SET_ERRNO(EILSEQ);
> > + goto done;
> > + }
> > +
> > + format++;
> > + str = endptr;
> > + matches++;
> > +
> > + } else if (*format == '\0') {
> > + goto done;
> > + } else if (isspace(*format)) {
> > + while (isspace(*format))
> > + format++;
> > + while (isspace(*str))
> > + str++;
> > + } else if (*format == *str) {
> > + format++;
> > + str++;
> > + } else {
> > + if (!matches)
> > + matches = EOF;
> > + goto done;
> > + }
> > + }
> > +
> > +done:
> > + return matches;
> > +}
> > +
> > +static __attribute__((unused, format(scanf, 2, 3)))
> > +int sscanf(const char *str, const char *format, ...)
> > +{
> > + va_list args;
> > + int ret;
> > +
> > + va_start(args, format);
> > + ret = vsscanf(str, format, args);
> > + va_end(args);
> > + return ret;
> > +}
> > +
> > static __attribute__((unused))
> > void perror(const char *msg)
> > {
> > diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c
> > index 093d0512f4c5..addbceb0b276 100644
> > --- a/tools/testing/selftests/nolibc/nolibc-test.c
> > +++ b/tools/testing/selftests/nolibc/nolibc-test.c
> > @@ -1277,6 +1277,64 @@ static int expect_vfprintf(int llen, int c, const char *expected, const char *fm
> > return ret;
> > }
> > +static int test_scanf(void)
> > +{
> > + unsigned long long ull;
> > + unsigned long ul;
> > + unsigned int u;
> > + long long ll;
> > + long l;
> > + void *p;
> > + int i;
> > +
> > + if (sscanf("", "foo") != EOF)
> > + return 1;
> > +
> > + if (sscanf("foo", "foo") != 0)
> > + return 2;
> > +
> > + if (sscanf("123", "%d", &i) != 1)
> > + return 3;
> > +
> > + if (i != 123)
> > + return 4;
> > +
> > + if (sscanf("a123b456c0x90", "a%db%uc%p", &i, &u, &p) != 3)
> > + return 5;
> > +
> > + if (i != 123)
> > + return 6;
> > +
> > + if (u != 456)
> > + return 7;
> > +
> > + if (p != (void *)0x90)
> > + return 8;
> > +
> > + if (sscanf("a b1", "a b%d", &i) != 1)
> > + return 9;
> > +
> > + if (i != 1)
> > + return 10;
> > +
> > + if (sscanf("a%1", "a%%%d", &i) != 1)
> > + return 11;
> > +
> > + if (i != 1)
> > + return 12;
> > +
> > + if (sscanf("1|2|3|4|5|6",
> > + "%d|%ld|%lld|%u|%lu|%llu",
> > + &i, &l, &ll, &u, &ul, &ull) != 6)
> > + return 13;
> > +
> > + if (i != 1 || l != 2 || ll != 3 ||
> > + u != 4 || ul != 5 || ull != 6)
> > + return 14;
> > +
> > + return 0;
>
> Can we simplify this code? It is hard to read code with too
> many conditions. Maybe defining an array test conditions
> instead of a series ifs.
I tried that and didn't find a way.
Any pointers are welcome.
> > +
> > +
> > static int run_vfprintf(int min, int max)
> > {
> > int test;
> > @@ -1298,6 +1356,7 @@ static int run_vfprintf(int min, int max)
> > CASE_TEST(char); EXPECT_VFPRINTF(1, "c", "%c", 'c'); break;
> > CASE_TEST(hex); EXPECT_VFPRINTF(1, "f", "%x", 0xf); break;
> > CASE_TEST(pointer); EXPECT_VFPRINTF(3, "0x1", "%p", (void *) 0x1); break;
> > + CASE_TEST(scanf); EXPECT_ZR(1, test_scanf()); break;
> > case __LINE__:
> > return ret; /* must be last */
> > /* note: do not set any defaults so as to permit holes above */
> >
>
> thanks,
> -- Shuah
On Fri, Aug 02, 2024 at 05:48:13PM +0200, Thomas Weißschuh wrote:
> > With all these libc functionality added, it isn't nolibc looks like :)
>
> Well :-)
>
> The main motivation is to provide kselftests compatibility.
> Maybe Willy disagrees.
No no I'm perfectly fine with adding the functions that developers use
or need to write their test or init tools. I don't have any strong
opinion on scanf(). Just like strtok(), I stopped using it 25 years ago
when I noticed that it never survives code evolutions, lacks a lot of
flexibility and is often strongly tied to your types (more than printf
where you can cast). But I perfectly understand that others are used to
it and would appreciate to have it, for example if it helps with command
line arguments.
> > > +static int test_scanf(void)
> > > +{
> > > + unsigned long long ull;
> > > + unsigned long ul;
> > > + unsigned int u;
> > > + long long ll;
> > > + long l;
> > > + void *p;
> > > + int i;
> > > +
> > > + if (sscanf("", "foo") != EOF)
> > > + return 1;
> > > +
> > > + if (sscanf("foo", "foo") != 0)
> > > + return 2;
> > > +
> > > + if (sscanf("123", "%d", &i) != 1)
> > > + return 3;
> > > +
> > > + if (i != 123)
> > > + return 4;
> > > +
> > > + if (sscanf("a123b456c0x90", "a%db%uc%p", &i, &u, &p) != 3)
> > > + return 5;
> > > +
> > > + if (i != 123)
> > > + return 6;
> > > +
> > > + if (u != 456)
> > > + return 7;
> > > +
> > > + if (p != (void *)0x90)
> > > + return 8;
> > > +
> > > + if (sscanf("a b1", "a b%d", &i) != 1)
> > > + return 9;
> > > +
> > > + if (i != 1)
> > > + return 10;
> > > +
> > > + if (sscanf("a%1", "a%%%d", &i) != 1)
> > > + return 11;
> > > +
> > > + if (i != 1)
> > > + return 12;
> > > +
> > > + if (sscanf("1|2|3|4|5|6",
> > > + "%d|%ld|%lld|%u|%lu|%llu",
> > > + &i, &l, &ll, &u, &ul, &ull) != 6)
> > > + return 13;
> > > +
> > > + if (i != 1 || l != 2 || ll != 3 ||
> > > + u != 4 || ul != 5 || ull != 6)
> > > + return 14;
> > > +
> > > + return 0;
> >
> > Can we simplify this code? It is hard to read code with too
> > many conditions. Maybe defining an array test conditions
> > instead of a series ifs.
>
> I tried that and didn't find a way.
> Any pointers are welcome.
I think it would be difficult by nature of varargs.
However, since you grouped some expressions, maybe a one-liner comment
between each scanf() to explain the intent of the test would make it
easier to follow. E.g:
/* test multiple naked numbers */
...
/* test numbers delimited with a character */
...
/* test multiple integer types at once */
etc. This allows the reviewer to more easly re-focus on the test they
were reading.
Willy
On 8/2/24 09:48, Thomas Weißschuh wrote:
> On 2024-07-31 17:01:09+0000, Shuah Khan wrote:
>> On 7/31/24 12:32, Thomas Weißschuh wrote:
>>> The implementation is limited and only supports numeric arguments.
>>
>> I would like to see more information in here. Why is this needed
>> etc. etc.
>
> Ack.
>
>>>
>>> Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
>>> ---
>>> tools/include/nolibc/stdio.h | 93 ++++++++++++++++++++++++++++
>>> tools/testing/selftests/nolibc/nolibc-test.c | 59 ++++++++++++++++++
>>> 2 files changed, 152 insertions(+)
>>>
>>> diff --git a/tools/include/nolibc/stdio.h b/tools/include/nolibc/stdio.h
>>> index c968dbbc4ef8..d63c45c06d8e 100644
>>> --- a/tools/include/nolibc/stdio.h
>>> +++ b/tools/include/nolibc/stdio.h
>>> @@ -348,6 +348,99 @@ int printf(const char *fmt, ...)
>>> return ret;
>>> }
>>> +static __attribute__((unused))
>>> +int vsscanf(const char *str, const char *format, va_list args)
>>
>> Is there a reason why you didn't use the same code in lib/vsprintf.c?
>> You could simply duplicate the code here?
>
> lib/vsprintf.c is GPL-2.0-only while nolibc is LGPL-2.1 OR MIT,
> so code reuse isn't really possible.
> Furthermore I think the vsprintf.c implements the custom kernel formats,
> while nolibc should use posix ones.
Ack.
>
>> With all these libc functionality added, it isn't nolibc looks like :)
>
> Well :-)
>
> The main motivation is to provide kselftests compatibility.
> Maybe Willy disagrees.
>
>>> +{
>>> +done:
>>> + return matches;
>>> +}
>>> +
>>> +static __attribute__((unused, format(scanf, 2, 3)))
>>> +int sscanf(const char *str, const char *format, ...)
>>> +{
>>> + va_list args;
>>> + int ret;
>>> +
>>> + va_start(args, format);
>>> + ret = vsscanf(str, format, args);
>>> + va_end(args);
>>> + return ret;
>>> +}
>>> +
>>> static __attribute__((unused))
>>> void perror(const char *msg)
>>> {
>>> diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c
>>> index 093d0512f4c5..addbceb0b276 100644
>>> --- a/tools/testing/selftests/nolibc/nolibc-test.c
>>> +++ b/tools/testing/selftests/nolibc/nolibc-test.c
>>> @@ -1277,6 +1277,64 @@ static int expect_vfprintf(int llen, int c, const char *expected, const char *fm
>>> return ret;
>>> }
>>> +static int test_scanf(void)
Is there a rationale for the return values 1 - 14. It will be
easier to understand if there are comments in the code.
>>> +{
>>> + unsigned long long ull;
>>> + unsigned long ul;
>>> + unsigned int u;
>>> + long long ll;
>>> + long l;
>>> + void *p;
>>> + int i;
>>> +
>>> + if (sscanf("", "foo") != EOF)
>>> + return 1;
>>> +
>>> + if (sscanf("foo", "foo") != 0)
>>> + return 2;
>>> +
>>> + if (sscanf("123", "%d", &i) != 1)
>>> + return 3;>>> +
>>> + if (i != 123)
>>> + return 4;
>>> +
>>> + if (sscanf("a123b456c0x90", "a%db%uc%p", &i, &u, &p) != 3)
>>> + return 5;
>>> +
>>> + if (i != 123)
>>> + return 6;
>>> +
>>> + if (u != 456)
>>> + return 7;
>>> +
>>> + if (p != (void *)0x90)
>>> + return 8;
>>> +
>>> + if (sscanf("a b1", "a b%d", &i) != 1)
>>> + return 9;
>>> +
>>> + if (i != 1)
>>> + return 10;
>>> +
>>> + if (sscanf("a%1", "a%%%d", &i) != 1)
>>> + return 11;
>>> +
>>> + if (i != 1)
>>> + return 12;
>>> +
>>> + if (sscanf("1|2|3|4|5|6",
>>> + "%d|%ld|%lld|%u|%lu|%llu",
>>> + &i, &l, &ll, &u, &ul, &ull) != 6)
>>> + return 13;
>>> +
>>> + if (i != 1 || l != 2 || ll != 3 ||
>>> + u != 4 || ul != 5 || ull != 6)
>>> + return 14;
>>> +
>>> + return 0;
>>
>> Can we simplify this code? It is hard to read code with too
>> many conditions. Maybe defining an array test conditions
>> instead of a series ifs.
>
> I tried that and didn't find a way.
> Any pointers are welcome.
I played with this some and couldn't think of way to simplify
this without making it hard to read. It would help adding
comments though.
thanks,
-- Shuah
© 2016 - 2026 Red Hat, Inc.