From 5464ae7d9e226586b79527cb445d892177b70271 Mon Sep 17 00:00:00 2001 From: Harald van Dijk Date: Fri, 23 Aug 2013 20:30:28 +1000 Subject: [BUILTIN] Use PRIdMAX instead of %j in printf 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. Reviewed-by: Jonathan Nieder Signed-off-by: Herbert Xu --- src/bltin/printf.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-) (limited to 'src') 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); } -- cgit 1.4.1