C error "warning: iteration 250u invokes undefined behaviour"

knobby67 · 04-22-2015, 02:02 AM

Hi just to say I'm using a gcc cross for coldfire, memset isn't avalible and {0} just sets element 1 to 0 andthe rest to random

veerain · 04-22-2015, 03:56 AM

Which gcc version? Try with 'gcc -std=c99'.

rtmistler · 04-22-2015, 06:30 AM

Or check the man page for your gcc and see what options it does have. I believe the standard statement is actually:

Code:

-std=gnu99

SoftSprocket · 04-22-2015, 04:07 PM

Quote:

Originally Posted by knobby67

Hi just to say I'm using a gcc cross for coldfire, memset isn't avalible and {0} just sets element 1 to 0 andthe rest to random

Stipulate -std=c99, -std=gnu99, -std=c11 or -std=gnu11 to use the array initializers. Memset is part of the standard library and should be declared in string.h.

knobby67 · 04-23-2015, 02:20 AM

Hi
Just to say this is an old gcc build provided by the hardware vendor.
It's an old cut down gcc cross for coldfire. It has no c libraries ( headers )It would be a joy to use things look like stdlib.h
I'm forced to use this because of compatabillity with vendor board libraries.
Putting a switch in make to tell it what version of c to use is well...
I'm sure if you've had experience of working on old embedded hardware you'll know what I mean. Think assembler with C syntax, well almost

rtmistler · 04-23-2015, 07:33 AM

Quote:

Originally Posted by knobby67

Hi
Just to say this is an old gcc build provided by the hardware vendor.
It's an old cut down gcc cross for coldfire. It has no c libraries ( headers )It would be a joy to use things look like stdlib.h
I'm forced to use this because of compatabillity with vendor board libraries.
Putting a switch in make to tell it what version of c to use is well...
I'm sure if you've had experience of working on old embedded hardware you'll know what I mean. Think assembler with C syntax, well almost

Given that, I would ABSOLUTELY make NO ASSUMPTIONS about auto-initialization of anything. This is where my old school overprotective coding makes the best sense.