- Do not use identifiers that are already declared
- For example, don't name a variable 'errno'
- Do not pass functions invalid values
- For floating point exception functions, only pass 0 or bitwise OR of floating point macros
- Do not modify the string returned by
setlocale()
- Do not call setjmp() in stupid places (eg. header files)
- Do not call longjmp() before calling setjmp()
- Do not call va_start() with a parameter declared with the register storage class, of array type, or a type that isn't compatible with the type after default argument promotions
- Do not try to get the address constant of a bit-field
- For example, do not:
&(t.member-designator)
- When functions fail, data structures often have indeterminate contents