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Posted by Jerry Stuckle on 09/30/07 19:49
Erik Wikström wrote:
> On 2007-09-30 18:49, Summercool wrote:
>> On Sep 30, 4:18 am, 7stud -- <dol...@excite.com> wrote:
>>> SpringFlowers AutumnMoon wrote:
>>>> we have no way
>>>> of knowing what we pass in could get changed.
>>> Sure you do. You look at the function's signature. In order to use
>>> someone else's library, you have to know the function's signature. And
>>> the signature explicitly tells you whether the value you pass in could
>>> be changed.
>> do you mean in C++? I tried to find signature in two C++ books and it
>> is not there. Google has a few results but it looks something like
>> prototype. Is signature the same as the function prototype in the .h
>> file?
>
> A signature is what is required to identify a function and includes
> return type, name of function and the types of the parameters, while it
> looks just like a prototype it is not. A prototype is something you
> write to satisfy your compiler while a signature identifies a function.
> Below are some examples of signatures, only the last can modify the
> values of its parameter.
>
No, the function's signature does not include the return type.
> void foo(int, float)
> std::string bar(const std::string&, int, int)
> void baz(std::string&)
>
Actually, these are prototypes. The signature is what's passed onto the
linker - perhaps something like "?foo@@YAXHM@Z". It's also generally
compiler dependent for C++ mangled names.
Also, I should clarify - the C++ function signature includes parameter
information. The C function signature is only dependent on the function
name and is almost always the name preceded by an underscore).
You can see the function signatures in a map file if you leave the names
mangled.
..
>> If so, don't we usually just include <___.h> and forget about
>> the rest. Documentation is fine although in some situation, the
>> descriptions is 2 lines, and notes and warnings are 4, 5 times that,
>> and the users' discussing it, holding different opinion is again 2, 3
>> times of that length.
>
> Unless you read the documentation how do you know which files to
> include? And what documentation are you reading which does not clearly
> specify the functionality of the functions described?
>
Exactly.
--
==================
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Jerry Stuckle
JDS Computer Training Corp.
jstucklex@attglobal.net
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