Malloc in D

[Dejan Lekic]

On Friday, 27 April 2012 at 09:05:12 UTC, Marcin wrote:
> Hi!
> I find code:
> [code]
> import c.stdlib;
> import c.stdlib;
> import std.outofmemory;
>
> class Foo{
> 	static void[] buffer;
> 	static int bufindex;
> 	static const int bufsize = 100;
> 	static this(){
> 		void *p;
> 		p = malloc(bufsize);
> 		if (!p)
> 		throw new OutOfMemory;
> 		gc.addRange(p, p + bufsize);
> 		buffer = p[0 .. bufsize];
> 	}
> 	static ~this(){
> 		if (buffer.length){
> 			gc.removeRange(buffer);
> 			free(buffer);
> 			buffer = null;
> 		}
> 	}
> 	new(uint sz){
> 		void *p;
> 		p = &buffer[bufindex];
> 		bufindex += sz;
> 		if (bufindex > buffer.length)
> 		throw new OutOfMemory;
> 		return p;
> 	}
> 	delete(void* p){
> 		assert(0);
> 	}
> 	static int mark(){
> 		return bufindex;
> 	}
>
> 	static void release(int i){
> 		bufindex = i;
> 	}
> }
> void test(){
> 	int m = Foo.mark();
> 	Foo f1 = new Foo; // allocate
> 	Foo f2 = new Foo; // allocate
> 	Foo.release(m); // deallocate f1 and f2
> }
> [/code]
> When I try compile i have some error:[code]
> vander at vander-VirtualBox:~/Pulpit/D$ gdc Memory.d -o Memory
> Memory.d:1: Error: module stdlib is in file 'c/stdlib.d' which 
> cannot be read
> import path[0] = 
> /usr/lib/i386-linux-gnu/gcc/i686-linux-gnu/4.4.5/../../../../../include/d/4.4.5/i686-linux-gnu
> import path[1] = 
> /usr/lib/i386-linux-gnu/gcc/i686-linux-gnu/4.4.5/../../../../../include/d/4.4.5
> vander at vander-VirtualBox:~/Pulpit/D$[/code]
> When i comment import c.stdlib;
> I have error
> [code]
> vander at vander-VirtualBox:~/Pulpit/D$ gdc Memory.d -o Memory
> Memory.d:11: Error: undefined identifier malloc
> Memory.d:11: Error: function expected before (), not __error of 
> type _error_
> Memory.d:13: Error: identifier 'OutOfMemory' is not defined
> Memory.d:13: Error: OutOfMemory is used as a type
> Memory.d:13: Error: new can only create structs, dynamic arrays 
> or class objects, not void's
> Memory.d:13: Error: can only throw class objects, not type void*
> Memory.d:14: Error: undefined identifier gc, did you mean 
> static import gcc?
> Error: no property 'addRange' for type 'TOK149'
> Memory.d:14: Error: function expected before (), not __error of 
> type TOK149
> Memory.d:19: Error: undefined identifier gc, did you mean 
> static import gcc?
> Error: no property 'removeRange' for type 'TOK149'
> Memory.d:19: Error: function expected before (), not __error of 
> type TOK149
> Memory.d:20: Error: undefined identifier free, did you mean 
> function fread?
> Memory.d:20: Error: function expected before (), not __error of 
> type _error_
> Memory.d:29: Error: identifier 'OutOfMemory' is not defined
> Memory.d:29: Error: OutOfMemory is used as a type
> Memory.d:29: Error: new can only create structs, dynamic arrays 
> or class objects, not void's
> Memory.d:29: Error: can only throw class objects, not type void*
> vander at vander-VirtualBox:~/Pulpit/D$
> [/code]
> What's can be wrong?

You probably have a very old GDC...

1) GC is a Struct inside core.memory so you need a line:

   GC gc;

2) You need to throw OutOfMemoryError which is defined in 
core.exception.

3) You need const(void*) pointers for GC methods.

So I first recommend you install latest GDC, and then modify your 
code to be more up-to-date.

I hope this helps.

Regards :)