<![CDATA[MISRA Discussion Forums - 6.7 Constants]]> https://forum.misra.org.uk/ Thu, 05 Nov 2026 15:13:14 +0000 MyBB <![CDATA[MISRA rule 7.1 Octal constants vs. Linux permissions]]> https://forum.misra.org.uk/showthread.php?tid=874 Wed, 25 Jan 2012 13:59:50 +0000 tharris]]> https://forum.misra.org.uk/showthread.php?tid=874 But code which sets and uses constants which represent Linux file permissions (see, for example, http://www.zzee.com/solutions/linux-perm...ml#numeric), are necessarily octal and code is more readable in that case in octal -- the "native" format for such constants.

Of course an octal number can be written, with the same digits, as hexadecimal, and that would meet the MISRA constraint. But IMHO would not meet the spirit of this rule, which is to avoid writing digits outside the base of the number by mistake. Writing a Linux file permissions constant as hex would mean that by mistake the developer could write a digit between 8 and F, and static analysis (compiler etc) would not catch it because it's legal hex. But illegal file permission digit.

Would people see this as a good place for a deviation from MISRA rule 7.1?]]> But code which sets and uses constants which represent Linux file permissions (see, for example, http://www.zzee.com/solutions/linux-perm...ml#numeric), are necessarily octal and code is more readable in that case in octal -- the "native" format for such constants.

Of course an octal number can be written, with the same digits, as hexadecimal, and that would meet the MISRA constraint. But IMHO would not meet the spirit of this rule, which is to avoid writing digits outside the base of the number by mistake. Writing a Linux file permissions constant as hex would mean that by mistake the developer could write a digit between 8 and F, and static analysis (compiler etc) would not catch it because it's legal hex. But illegal file permission digit.

Would people see this as a good place for a deviation from MISRA rule 7.1?]]> <![CDATA[Rule 7.1 For Macro Arguments?]]> https://forum.misra.org.uk/showthread.php?tid=843 Mon, 12 Sep 2011 14:16:25 +0000 gs]]> https://forum.misra.org.uk/showthread.php?tid=843
Does rule 7.1, "Octal constants (other than zero) and octal escape sequences shall not be used", apply to function-like macro arguments? For example:
Code:
#define MACRO(a)    XYZ_##a

int MACRO(01);

Is the '01' argument to MACRO() a violation of this rule?]]>
Does rule 7.1, "Octal constants (other than zero) and octal escape sequences shall not be used", apply to function-like macro arguments? For example:
Code:
#define MACRO(a)    XYZ_##a

int MACRO(01);

Is the '01' argument to MACRO() a violation of this rule?]]> <![CDATA[What about '\\0'?]]> https://forum.misra.org.uk/showthread.php?tid=17 Wed, 08 Dec 2004 21:03:37 +0000 gs]]> https://forum.misra.org.uk/showthread.php?tid=17
I appreciate your time in advance.]]>
I appreciate your time in advance.]]>