Re: [Dev-C++] Crash with macro to template conversion
Open Source C & C++ IDE for Windows
Brought to you by:
claplace
Menu
▾
▴
Re: [Dev-C++] Crash with macro to template conversion
|
From: David M. <ci...@ya...> - 2004-02-28 23:22:11
|
you apparently did not read the end of my message,
I know how to create a pointer to a pointer (**) I haven't heard
about a
refrence to a pointer (&* ?), what is the syntax for such a variable?
----- Original Message -----
From: "Per Westermark" <pw...@ia...>
To: "David McKen" <ci...@ya...>
Cc: "Mailing List, Dev-Cpp" <dev...@li...>
Sent: Saturday, February 28, 2004 5:27 AM
Subject: Re: [Dev-C++] Crash with macro to template conversion
> But you have not fixed the declaration of the ptr parameter yet.
Any
> allocations you make will behave ok inside the create() function,
but the
> caller will never get the value of the allocated pointer! You
REALLY MUST
> change del parameter declaration to either be a pointer to a
pointer, or a
> reference to a pointer!
>
> /Per W
>
> On Fri, 27 Feb 2004, David McKen wrote:
>
> > Sorry about that the correct definition is:
> > template<class T>
> > void create(T * ptr, int number, char * f_name = __FILE__, int
l_num
> > =
> > __LINE__)
> > {
> > ptr = new T[number];
> > if ( !ptr )
> > {
> > perror("malloc failure");
> > fprintf( stderr, "Malloc failure @ %s:%d\n", f_name, l_num );
> > abort();
> > }
> > }
> >
> > All the exception stuff was just trying to figure out if an error
is
> > even
> > occuring.
> >
> > I am trying to keep to convention. The macro is not my code but
code
> > I am
> > trying to replace. I am very tempted to change it but I also have
> > RECREATE
> > (wraps realloc()) and DESTROY (wraps free() ) which also need to
be
> > replaced. I could use macros to alter the function call but I am
> > trying to
> > remove all the macros I can (got some linked list macros to
replace
> > as well)
> >
> > So...How does one create a refrence to a pointer?
> >
> > ----- Original Message -----
> > From: "Per Westermark" <pw...@ia...>
> > To: "David McKen" <ci...@ya...>
> > Cc: "Mailing List, Dev-Cpp" <dev...@li...>
> > Sent: Friday, February 27, 2004 7:08 AM
> > Subject: Re: [Dev-C++] Crash with macro to template conversion
> >
> >
> > > First of all - your create template function is declared to
return
> > void,
> > > so why do you end it with return ptr?
> > >
> > > Second, you send in a T* ptr parameter. Note that since C++
uses
> > > call-by-value, this will behave like a lokal variable, i.e any
> > assign to
> > > ptr will not reflect back to the caller. You should change the
> > first
> > > parameter of create to be a reference to a pointer. That way,
the
> > assign
> > > to ptr will reflect back to the variable obj of the caller.
> > >
> > > /Per W
> > >
> > > On Fri, 27 Feb 2004, David McKen wrote:
> > >
> > > > Ok here is my problem.
> > > >
> > > > I want to replace:
> > > > #define CREATE(result, type, number) \
> > > > do \
> > > > { \
> > > > if (!((result) = (type *) calloc ((number),
sizeof(type)))) \
> > > > { \
> > > > perror("malloc failure"); \
> > > > fprintf(stderr, "Malloc failure @ %s:%d\n", __FILE__,
> > __LINE__ );
> > > > \
> > > > abort(); \
> > > > } \
> > > > } while(0)
> > > >
> > > > With it's C++ equivalent.
> > > >
> > > > So far I have:
> > > > #define CREATE(result, type, num)
create<type>((result),(num))
> > > > template<class T>
> > > > void create(T * ptr, int number, char * f_name = __FILE__,
int
> > l_num
> > > > =
> > > > __LINE__)
> > > > {
> > > > try {
> > > > ptr = new T[number];
> > > > }
> > > > catch(bad_alloc& b)
> > > > {
> > > > perror("malloc failure");
> > > > fprintf( stderr, "Malloc failure @ %s:%d\n", f_name,
l_num );
> > > > abort();
> > > > }
> > > > if ( !ptr )
> > > > {
> > > > perror("malloc failure");
> > > > fprintf( stderr, "Malloc failure @ %s:%d\n", f_name,
l_num );
> > > > abort();
> > > > }
> > > > return ptr;
> > > > }
> > > >
> > > > But the program crashes after the function call when any
attempt
> > to
> > > > acces
> > > > the data occours:
> > > > e.g.
> > > > OBJ_DATA * obj;
> > > > CREATE( obj , OBJ_DATA, 1 );
> > > >
> > > > obj->some_field = 5; //Crashes here and obj = 0x0 from gdb.
> > > >
> > > > Thanks in Advance
> > > > David McKen
> > > >
> > > >
> > > > __________________________________
> > > > Do you Yahoo!?
> > > > Get better spam protection with Yahoo! Mail.
> > > > http://antispam.yahoo.com/tools
> > > >
> > > >
> > > > -------------------------------------------------------
> > > > SF.Net is sponsored by: Speed Start Your Linux Apps Now.
> > > > Build and deploy apps & Web services for Linux with
> > > > a free DVD software kit from IBM. Click Now!
> > > > http://ads.osdn.com/?ad_id=1356&alloc_id=3438&op=click
> > > > _______________________________________________
> > > > Dev-cpp-users mailing list
> > > > Dev...@li...
> > > > TO UNSUBSCRIBE:
http://www23.brinkster.com/noicys/devcpp/ub.htm
> > > > https://lists.sourceforge.net/lists/listinfo/dev-cpp-users
> > > >
> > >
> > >
> > >
> > > -------------------------------------------------------
> > > SF.Net is sponsored by: Speed Start Your Linux Apps Now.
> > > Build and deploy apps & Web services for Linux with
> > > a free DVD software kit from IBM. Click Now!
> > > http://ads.osdn.com/?ad_id=1356&alloc_id=3438&op=click
> > > _______________________________________________
> > > Dev-cpp-users mailing list
> > > Dev...@li...
> > > TO UNSUBSCRIBE: http://www23.brinkster.com/noicys/devcpp/ub.htm
> > > https://lists.sourceforge.net/lists/listinfo/dev-cpp-users
> >
> >
> > __________________________________
> > Do you Yahoo!?
> > Get better spam protection with Yahoo! Mail.
> > http://antispam.yahoo.com/tools
> >
> >
> > -------------------------------------------------------
> > SF.Net is sponsored by: Speed Start Your Linux Apps Now.
> > Build and deploy apps & Web services for Linux with
> > a free DVD software kit from IBM. Click Now!
> > http://ads.osdn.com/?ad_id=1356&alloc_id=3438&op=click
> > _______________________________________________
> > Dev-cpp-users mailing list
> > Dev...@li...
> > TO UNSUBSCRIBE: http://www23.brinkster.com/noicys/devcpp/ub.htm
> > https://lists.sourceforge.net/lists/listinfo/dev-cpp-users
> >
>
>
>
> -------------------------------------------------------
> SF.Net is sponsored by: Speed Start Your Linux Apps Now.
> Build and deploy apps & Web services for Linux with
> a free DVD software kit from IBM. Click Now!
> http://ads.osdn.com/?ad_id=1356&alloc_id=3438&op=click
> _______________________________________________
> Dev-cpp-users mailing list
> Dev...@li...
> TO UNSUBSCRIBE: http://www23.brinkster.com/noicys/devcpp/ub.htm
> https://lists.sourceforge.net/lists/listinfo/dev-cpp-users
__________________________________
Do you Yahoo!?
Get better spam protection with Yahoo! Mail.
http://antispam.yahoo.com/tools
|
