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+---- Thread: Rule #3-2-3 and Forward Declarations? (/showthread.php?tid=766)
Rule #3-2-3 and Forward Declarations? - gs - 18-08-2010
Does rule #3-2-3 prohibit the use of forward declarations in separate files? For example, if a file, a.h, contained "class B;" and another file, c.h, #include'd a.h and contained a definition for class D which contained "friend class B;", would the rule permit such?
Re: Rule #3-2-3 and Forward Declarations? - ggoulas - 17-09-2015
I am interested by the answer to this question. Should forward declaration such as
class a_class;
be allowed by rule 3-2-3 anywhere in source files?
Could misra reply to this please?
Re: Rule #3-2-3 and Forward Declarations? - misra cpp - 11-10-2016
This rule does not preclude the use of friend or forward reference statements, but these must be in a separate header file.
A future edition may reconsider this point
Re: Rule #3-2-3 and Forward Declarations? - gs - 24-03-2017
I don't understand. Are you saying the "one and only one file" requirement does not apply to friend declarations and forward references?
Re: Rule #3-2-3 and Forward Declarations? - misra cpp - 10-07-2017
This rule does not preclude the use of friend or forward reference statements, but these must be in a separate header file.
A future edition may reconsider this point
The second question, your examples are compliant - the objective is to ensure that class definitions are only made in one file (and not repeated in multiple translation units)"