On 12/03/2012 05:59 PM, Harald van Dijk wrote:
> On 12/03/2012 08:42 AM, Roy wrote:
>> MSYS libc does not support %j[dXx] format, only %ll[dXx] is supported.
>>
>> diff --git a/src/bltin/printf.c b/src/bltin/printf.c
>> index 893295c..12ce660 100644
>> --- a/src/bltin/printf.c
>> +++ b/src/bltin/printf.c
>> @@ -319,11 +319,12 @@ mklong(const char *str, const char *ch)
>> char *copy;
>> size_t len;
>>
>> - len = ch - str + 3;
>> + len = ch - str + 4;
>> STARTSTACKSTR(copy);
>> copy = makestrspace(len, copy);
>> - memcpy(copy, str, len - 3);
>> - copy[len - 3] = 'j';
>> + memcpy(copy, str, len - 4);
>> + copy[len - 4] = 'l';
>> + copy[len - 3] = 'l';
>> copy[len - 2] = *ch;
>> copy[len - 1] = '\0';
>> return (copy);
>
> The calling code uses the result to print intmax_t and uintmax_t values.
> Printing intmax_t values with %lld is wrong, this will only work if
> intmax_t is really a typedef for long long (which may be true on your
> system, but is not required by the standard).
>
> The other patch that Jonathan linked to should work just fine.
Here's a slightly tweaked version of that patch. Regardless of whether
PRIdMAX is defined as "jd" or as "lld", the use of memcpy here, first
copying "jd"/"lld" and the null byte, and only changing the 'd' after
that, surprisingly results in slightly shorter object code than the
original byte-by-byte approach, even though memcpy is fully inlined.
Perhaps that could be a reason for applying this, even if the original
reason for it, making the code work on not-quite-conforming systems,
isn't good enough to get it in dash.
Tested with normal glibc, and with glibc hacked to not provide PRIdMAX.
Cheers,
Harald
diff --git a/src/bltin/printf.c b/src/bltin/printf.c
index 893295c..5f9e81c 100644
--- a/src/bltin/printf.c
+++ b/src/bltin/printf.c
@@ -316,16 +316,24 @@ out:
static char *
mklong(const char *str, const char *ch)
{
+ /*
+ * Replace a string like "%92.3u" with "%92.3"PRIuMAX.
+ *
+ * Although C99 does not guarantee it, we assume PRIiMAX,
+ * PRIoMAX, PRIuMAX, PRIxMAX, and PRIXMAX are all the same
+ * as PRIdMAX with the final 'd' replaced by the corresponding
+ * character.
+ */
+
char *copy;
size_t len;
- len = ch - str + 3;
+ len = ch - str + sizeof(PRIdMAX);
STARTSTACKSTR(copy);
copy = makestrspace(len, copy);
- memcpy(copy, str, len - 3);
- copy[len - 3] = 'j';
+ memcpy(copy, str, len - sizeof(PRIdMAX));
+ memcpy(copy + len - sizeof(PRIdMAX), PRIdMAX, sizeof(PRIdMAX));
copy[len - 2] = *ch;
- copy[len - 1] = '\0';
return (copy);
}
