On 13.02.2019, at 22:57, Thomas Petazzoni thomas.petazzoni@bootlin.com wrote:
Commit 51c2345bd24837f9f67f16268da6dc71573f1325 ("Roll CRC16-CCITT into the hash infrastructure") has modified the crc16 code by adding a C99-style loop where the loop iterator is declared inside the for() statement. This breaks the build with old compiler such as gcc 4.7, that do not default to C99:
I thought U-Boot now has a requirement of GCC6 or newer (i.e. C99 being the default C dialect). While there’s still a few distributions out there that use legacy compiler versions, we might want to consider having the same requirement for the host tools.
./tools/../lib/crc16.c: In function 'crc16_ccitt': ./tools/../lib/crc16.c:70:2: error: 'for' loop initial declarations are only allowed in C99 mode ./tools/../lib/crc16.c:70:2: note: use option -std=c99 or -std=gnu99 to compile your code
Switching to the regular coding style used in the rest of U-Boot allows to fix this build issue.
At this point in time (although Tom will have the final word), I would strongly encourage us adopting C99 in our coding style.
C99 has been around for a while now (it will be 20 years this year that the standard came out) and we already have seen ISO/IEC 9899:2011 and ISO/IEC 9899:2018 published. Note that these also improvements for system-level development (stdatomics.h and stdalign.h are underutilised extensions for that purpose)...
Signed-off-by: Thomas Petazzoni thomas.petazzoni@bootlin.com
lib/crc16.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/lib/crc16.c b/lib/crc16.c index f46ba727c9..89d2cff131 100644 --- a/lib/crc16.c +++ b/lib/crc16.c @@ -67,7 +67,9 @@ static const uint16_t crc16_tab[] = {
uint16_t crc16_ccitt(uint16_t cksum, const unsigned char *buf, int len)
If we are trying to turn back the wheel of time, then even the const modifier would be up for discussion: after all, this was a GNU extension in gnu89…
{
- for (int i = 0; i < len; i++)
int i;
for (i = 0; i < len; i++) cksum = crc16_tab[((cksum>>8) ^ *buf++) & 0xff] ^ (cksum << 8);
return cksum;
-- 2.20.1