«

Hi,


> Dear Norbert:
>
> Many posters have commented that it is bad idea
> to compile C code using a C++ compiler.

Sorry gusy - i think my answer was (again) too short

I'm using gcc for normal compiling and running of my project (.h and .c
files).

But sometimes (only for the creation of warnings) I use the g++ because
it checks some missing type-casts and warns me if I switch the usage of
booleans and enums (I've got some extended return values). The gcc does
NOT recognises a
return FALSE;
when the function should return some enum. (gcc and g++ called with the
same params)

But I'm running only the gcc-compiled stuff.

Greetings:


Norbert

Norbert Leister wrote:

> when I write
>
> my_pointer = malloc(struct_size);
>
> i get an error compiling the code with g++.

g++ is a C++ compiler. If you have problems with that different
[naughty words deleted] language, ask them in <news:comp.lang.c++>. If
your problem is specifically with g++, ask in a gnu-related newsgroup.

> I sometimes use compiling my
> c-code in g++ go get some extendend compiler warnings.

No, you get C++ warnings. If you are compiling C, just turn on the
warnings you want with gcc. The choices are large, and the
documentation is explicit. It is a common error, but an error
nonetheless, to think that warnings about C++ errors are useful for C
programs. In fact, using a C++ compiler to compile C programs is just
silly as well as wrong. C++ compilers and C compilers handle different
languages. You could use a Fortran compiler and get "extended compiler
warnings," but would you?

> So i use a
> typecast for all mallocs I'm using...

That's silly. Why don't you use the silly C++ casts instead, since a
C++ compiler might well "warn" you that C-style casts are a bad idea?

Norbert Leister <> writes:
[...]
> I'm using gcc for normal compiling and running of my project (.h and
> .c files).
>
> But sometimes (only for the creation of warnings) I use the g++
> because it checks some missing type-casts and warns me if I switch the
> usage of booleans and enums (I've got some extended return
> values). The gcc does NOT recognises a
> return FALSE;
> when the function should return some enum. (gcc and g++ called with
> the same params)
>
> But I'm running only the gcc-compiled stuff.

The "missing type-casts" (BTW, the term is "casts", not "type-casts")
are probably ones that are required in C++ but not in C. g++ is
telling you things that are not relevant to C. (It will also print an
error message if you use "class" as an identifier, which is perfectly
legal in C.)

Using a C++ compiler to find additional errors in C code can make
sense *if* you realize which warnings are relevant and which are not.
You don't need to modify your code to eliminate *all* C++ diagnostics.

--
Keith Thompson (The_Other_Keith) kst- <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <*> <http://users.sdsc.edu/~kst>
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"

Norbert Leister wrote, On 02/05/07 18:37:
> Hi,
>
>
> > Dear Norbert:
> >
> > Many posters have commented that it is bad idea
> > to compile C code using a C++ compiler.
>
> Sorry gusy - i think my answer was (again) too short
>
> I'm using gcc for normal compiling and running of my project (.h and .c
> files).
>
> But sometimes (only for the creation of warnings) I use the g++ because
> it checks some missing type-casts and warns me if I switch the usage of
> booleans and enums (I've got some extended return values). The gcc does
> NOT recognises a
> return FALSE;
> when the function should return some enum. (gcc and g++ called with the
> same params)
>
> But I'm running only the gcc-compiled stuff.

You are still using the wrong tool for the job. If you want you C code
analysed use a tool designed to analyse C code, not a tool designed to
compile C++ code. They are different problems. Had you read the
comp.lang.c FAQ at http://c-faq.com you would have found references to
Lint, one version of which is available from http://www.splint.org/
--
Flash Gordon

Norbert Leister wrote:

> Hi,
>
>
> > Dear Norbert:
> >
> > Many posters have commented that it is bad idea
> > to compile C code using a C++ compiler.
>
> Sorry gusy - i think my answer was (again) too short
>
> I'm using gcc for normal compiling and running of my project (.h and
> .c files).
>
> But sometimes (only for the creation of warnings) I use the g++
> because it checks some missing type-casts

Can you give some examples of these "missing" casts?




Brian

Norbert Leister wrote:
> Hi,
>
>
>> Dear Norbert:
>>
>> Many posters have commented that it is bad idea
>> to compile C code using a C++ compiler.
>
> Sorry gusy - i think my answer was (again) too short
>
> I'm using gcc for normal compiling and running of my project (.h and .c
> files).
>
> But sometimes (only for the creation of warnings) I use the g++ because
> it checks some missing type-casts and warns me if I switch the usage of
> booleans and enums (I've got some extended return values). The gcc does
> NOT recognises a
> return FALSE;
> when the function should return some enum. (gcc and g++ called with the
> same params)
>
Consider using bool if you are only building with gcc.

--
Ian Collins.

Ian Collins <ian-> writes:
[...]
>> But sometimes (only for the creation of warnings) I use the g++ because
>> it checks some missing type-casts and warns me if I switch the usage of
>> booleans and enums (I've got some extended return values). The gcc does
>> NOT recognises a
>> return FALSE;
>> when the function should return some enum. (gcc and g++ called with the
>> same params)
>>
> Consider using bool if you are only building with gcc.

To be clear, gcc (in C mode) doesn't support a C++-style "bool"
keyword; it does support the _Bool keyword and the <stdbool.h> header,
as defined by C99. (Note that <stdbool.h> is provided as part of gcc
itself, unlike most headers which are part of a distinct runtime
library.)

--
Keith Thompson (The_Other_Keith) kst- <http://www.ghoti.net/~kst>
San Diego Supercomputer Center <*> <http://users.sdsc.edu/~kst>
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"

On May 2, 10:37 am, Norbert Leister <makar...@web.de> wrote:
> >
> > Many posters have commented that it is bad idea
> > to compile C code using a C++ compiler.
>
> Sorry gusy - i think my answer was (again) too short
>
> I'm using gcc for normal compiling and running of my project (.h and .c
> files).
>
> But sometimes (only for the creation of warnings) I use the g++ because
> it checks some missing type-casts and warns me if I switch the usage of
> booleans and enums (I've got some extended return values). The gcc does
> NOT recognises a
> return FALSE;
> when the function should return some enum. (gcc and g++ called with the
> same params)
>
> But I'm running only the gcc-compiled stuff.

Although this might strictly be off-topic, what params are you giving
to gcc? I'll be amazed if running your code through a C++ compiler
will give you any warnings relevant to C which you can't get by giving
appropriate parameters to gcc. Since it may also give you lots of
incorrect warnings and errors due to the differences between C and C+
+, it's a very strange way to work.

J. J. Farrell wrote:
> On May 2, 10:37 am, Norbert Leister <makar...@web.de> wrote:
>> >
>> > Many posters have commented that it is bad idea
>> > to compile C code using a C++ compiler.
>>
>> Sorry gusy - i think my answer was (again) too short
>>
>> I'm using gcc for normal compiling and running of my project (.h and .c
>> files).
>>
>> But sometimes (only for the creation of warnings) I use the g++ because
>> it checks some missing type-casts and warns me if I switch the usage of
>> booleans and enums (I've got some extended return values). The gcc does
>> NOT recognises a
>> return FALSE;
>> when the function should return some enum. (gcc and g++ called with the
>> same params)
>>
>> But I'm running only the gcc-compiled stuff.
>
> Although this might strictly be off-topic, what params are you giving
> to gcc? I'll be amazed if running your code through a C++ compiler
> will give you any warnings relevant to C which you can't get by giving
> appropriate parameters to gcc. Since it may also give you lots of
> incorrect warnings and errors due to the differences between C and C+
> +, it's a very strange way to work.
>
It looks like he is using something like

typedef enum {FALSE,TRUE} Bool;
typedef enum {GOOD,BAD,UGLY} Result;

Bool f() { return UGLY; }

which gcc -Wall -ansi -pedantic is quite happy with.

--
Ian Collins.

Flash Gordon said:

> Norbert Leister wrote, On 02/05/07 18:37:
>>
>> I'm using gcc for normal compiling and running of my project (.h and
>> .c files).
>>
>> But sometimes (only for the creation of warnings) I use the g++
>> because it checks some missing type-casts and warns me if I switch
>> the usage of booleans and enums (I've got some extended return
>> values).

<snip>

> You are still using the wrong tool for the job. If you want you C code
> analysed use a tool designed to analyse C code, not a tool designed to
> compile C++ code.

No, Flash, he's right - if he wants more warnings, using a compiler for
a different language is a great way to get them. Personally, for this
purpose I can wholeheartedly recommend using a COBOL compiler.

--
Richard Heathfield
"Usenet is a strange place" - dmr 29/7/1999
http://www.cpax.org.uk
email: rjh at the above domain, - www.