[9fans] Function args not checked

[9fans] Function args not checked

[Rodolfo (kix)]

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Hi,

I have this definitions:

extern Elem mkoid(Ints *oid); // asn1.h
Ints * snmp_mkoid(char *str); // snmp_asn1.h
char * oids[MAX];

and, this:

myElem = mkoid(snmp_mkoid(oids[0]));

The 8c returns:

x.c:216 function args not checked: snmp_mkoid
x.c:216 argument prototype mismatch "INT" for "IND STRUCT Ints": mkoid

why?

--
Rodolfo García "kix"

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Re: [9fans] Function args not checked

[geoff]

It sounds like the header that declares snmp_mkoid isn't being
included in the file that contains

myElem = mkoid(snmp_mkoid(oids[0]));

Re: [9fans] Function args not checked

[Rodolfo (kix)]

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Yes!

thanks

On 4/17/06, geoff@collyer.net <geoff@collyer.net> wrote:
>
> It sounds like the header that declares snmp_mkoid isn't being
> included in the file that contains
>
> myElem = mkoid(snmp_mkoid(oids[0]));
>
>


--
Rodolfo García "kix"

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Re: [9fans] Function args not checked

[jmk]

As an aside, when you declare prototypes I find it is best to
only give the types of the parameters and not declare identifiers,
e.g.
	extern Elem mkoid(Ints *); // asn1.h
rather than
	extern Elem mkoid(Ints *oid); // asn1.h
This prevents confusion in environments where there is overuse
of the pre-processor and the identifier gets substituted.

--jim

On Mon Apr 17 02:51:00 EDT 2006, rodolfogarciap@gmail.com wrote:
> 
> Hi,
> 
> I have this definitions:
> 
> extern Elem mkoid(Ints *oid); // asn1.h
> Ints * snmp_mkoid(char *str); // snmp_asn1.h
> char * oids[MAX];
> 
> and, this:
> 
> myElem = mkoid(snmp_mkoid(oids[0]));
> 
> The 8c returns:
> 
> x.c:216 function args not checked: snmp_mkoid
> x.c:216 argument prototype mismatch "INT" for "IND STRUCT Ints": mkoid
> 
> why?
> 
> --
> Rodolfo García "kix"
> 

Re: [9fans] Function args not checked

["Nils O. Selåsdal"]

jmk@plan9.bell-labs.com wrote:
> As an aside, when you declare prototypes I find it is best to
> only give the types of the parameters and not declare identifiers,
> e.g.
> 	extern Elem mkoid(Ints *); // asn1.h
> rather than
> 	extern Elem mkoid(Ints *oid); // asn1.h
> This prevents confusion in environments where there is overuse
> of the pre-processor and the identifier gets substituted.

Valid point,but I find the names quite helpful and of documentary
value -  perhaps it's a defect of mine after reading too much
non-obvious code.

Re: [9fans] Function args not checked

[David Leimbach]

On 4/17/06, "Nils O. Selåsdal" <noselasd@asgaard.homelinux.org> wrote:
> jmk@plan9.bell-labs.com wrote:
> > As an aside, when you declare prototypes I find it is best to
> > only give the types of the parameters and not declare identifiers,
> > e.g.
> >       extern Elem mkoid(Ints *); // asn1.h
> > rather than
> >       extern Elem mkoid(Ints *oid); // asn1.h
> > This prevents confusion in environments where there is overuse
> > of the pre-processor and the identifier gets substituted.
>
> Valid point,but I find the names quite helpful and of documentary
> value -  perhaps it's a defect of mine after reading too much
> non-obvious code.
>

Well a lot of people fall back to header files for documentation
purposes, and looking headers to figure out which of the "char *'s" is
a source and which is a destination in some cases is nice.

Nothing that can't be solved with good comments and man pages though.

Re: [9fans] Function args not checked

[jmk]

Prototypes are not documentation.

On Mon Apr 17 11:29:34 EDT 2006, leimy2k@gmail.com wrote:
> On 4/17/06, "Nils O. Selåsdal" <noselasd@asgaard.homelinux.org> wrote:
> > jmk@plan9.bell-labs.com wrote:
> > > As an aside, when you declare prototypes I find it is best to
> > > only give the types of the parameters and not declare identifiers,
> > > e.g.
> > >       extern Elem mkoid(Ints *); // asn1.h
> > > rather than
> > >       extern Elem mkoid(Ints *oid); // asn1.h
> > > This prevents confusion in environments where there is overuse
> > > of the pre-processor and the identifier gets substituted.
> >
> > Valid point,but I find the names quite helpful and of documentary
> > value -  perhaps it's a defect of mine after reading too much
> > non-obvious code.
> >
> 
> Well a lot of people fall back to header files for documentation
> purposes, and looking headers to figure out which of the "char *'s" is
> a source and which is a destination in some cases is nice.
> 
> Nothing that can't be solved with good comments and man pages though.

Re: [9fans] Function args not checked

[Paul Lalonde]

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On 17-Apr-06, at 8:31 AM, jmk@plan9.bell-labs.com wrote:

> Prototypes are not documentation.

Absolutely.  But they have a better chance of reflecting reality.

Not everyone is blessed to work on good code bases.  Until then, I'll  
keep "documenting" my prototypes with good names.

Paul

>
> On Mon Apr 17 11:29:34 EDT 2006, leimy2k@gmail.com wrote:
>> On 4/17/06, "Nils O. Selåsdal" <noselasd@asgaard.homelinux.org>  
>> wrote:
>>> jmk@plan9.bell-labs.com wrote:
>>>> As an aside, when you declare prototypes I find it is best to
>>>> only give the types of the parameters and not declare identifiers,
>>>> e.g.
>>>>       extern Elem mkoid(Ints *); // asn1.h
>>>> rather than
>>>>       extern Elem mkoid(Ints *oid); // asn1.h
>>>> This prevents confusion in environments where there is overuse
>>>> of the pre-processor and the identifier gets substituted.
>>>
>>> Valid point,but I find the names quite helpful and of documentary
>>> value -  perhaps it's a defect of mine after reading too much
>>> non-obvious code.
>>>
>>
>> Well a lot of people fall back to header files for documentation
>> purposes, and looking headers to figure out which of the "char  
>> *'s" is
>> a source and which is a destination in some cases is nice.
>>
>> Nothing that can't be solved with good comments and man pages though.

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Re: [9fans] Function args not checked

[Skip Tavakkolian]

>> Prototypes are not documentation.
>
> Absolutely.  But they have a better chance of reflecting reality.
>
> Not everyone is blessed to work on good code bases.  Until then, I'll
> keep "documenting" my prototypes with good names.

variable naming conventions are not enforced by the compiler; they
could be misleading.  why not use an ide - e.g.  eclipse is available
for many platforms - or just document the code.  using cweb will
exhibit your STRONG commitment to good documentation :)

Re: [9fans] Function args not checked

[Don Bailey]

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> variable naming conventions are not enforced by the compiler; they
> could be misleading.  why not use an ide - e.g.  eclipse is available
> for many platforms - or just document the code.  using cweb will
> exhibit your STRONG commitment to good documentation :)
>

I used to have a problem deciding how to keep track of
IN and OUT arguments in functions. Rather than bothering
to clutter up prototypes with names, I came up with this
simple technique:

	for
		anyfunction(IN * A, IN * B, IN * C, OUT * A)

Variables used as input to the given function will be sent
first, in alphabetical order by type. Output variables will be
sent next, alphabetically by type.

Thus,
	str->dup(char *, char ** );

Even without the second indirection giving us an obvious
clue, we know that the first variable is input and the second
is output.

Because I stick to this as a strict part of my API, I never have
to check the source to remind myself what I'm doing.

Just thought I'd give my two cents.

Don "north" Bailey



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Re: [9fans] Function args not checked

[Victor Nazarov]

jmk@plan9.bell-labs.com wrote:

>As an aside, when you declare prototypes I find it is best to
>only give the types of the parameters and not declare identifiers,
>e.g.
>	extern Elem mkoid(Ints *); // asn1.h
>rather than
>	extern Elem mkoid(Ints *oid); // asn1.h
>This prevents confusion in environments where there is overuse
>of the pre-processor and the identifier gets substituted.
>
>
It's just an evidence of preprocessor's danger. Let's use enums. IMHO,
prototypes are quite good documentation sometimes.
--
Victor Nazarov

Re: [9fans] Function args not checked

[Devon H. O'Dell]

2006/4/17, Victor Nazarov <vir@comtv.ru>:
> jmk@plan9.bell-labs.com wrote:
>
> >As an aside, when you declare prototypes I find it is best to
> >only give the types of the parameters and not declare identifiers,
> >e.g.
> >       extern Elem mkoid(Ints *); // asn1.h
> >rather than
> >       extern Elem mkoid(Ints *oid); // asn1.h
> >This prevents confusion in environments where there is overuse
> >of the pre-processor and the identifier gets substituted.
> >
> >
> It's just an evidence of preprocessor's danger. Let's use enums. IMHO,
> prototypes are quite good documentation sometimes.

Until someone reorders arguments and forgets to update the prototype
to reflect them. Using argument names in your prototypes is not an
excuse to not write documentation on your API. It is an excuse to be
lazy.

--Devon

> --
> Victor Nazarov
>
>