Overloading doesn't work like described in The D programming language
Hi!
On pages 145 and 146 (ยง 5.5.1) of The D programming language there is
an example with overloading a function with uint, long, and a
parameterized type. I tried to reproduce that using a similar example:
code
module main;
import std.stdio;
void overloadme(uint number)
{
writeln(This is overloadme with uint.);
}
void overloadme(long number)
{
writeln(This is overloadme with long.);
}
void overloadme(T)(T number)
{
writeln(Generic overloadme called.);
}
int main(string[] argv)
{
overloadme(25);
overloadme(Bla);
writeln(\nFinished);
readln();
return 0;
}
/code
However, if I try to compile that code, the compiler yields an error in
line 15:
Error: template main.overloadme(T) conflicts with function
main.overloadme at main.d(5)
In the book it says that non-generic functions are generally preferred
to generic functions, even when the non-generic function need an
implicit conversion. But in my case that doesn't work.
Can anyone explain me what's going on here? Is the example in the book
wrong or did I misinterpret something?
Best regards
Michael
Re: Translation of C struct to D
Am 2011-11-16 23:23, schrieb Trass3r: If I try to cast with register_chrdev(0, (char*)DEVICE_NAME, fops); the following error appears: C style cast illegal, use cast(char*)DEVICE_NAME Or use DEVICE_NAME.ptr Compilation now succeeded, but when I try to load with insmod, the following errors appear: Nov 17 15:03:49 eeepc1104 kernel: [43799.326876] hello: Unknown symbol _D3std6string12__ModuleInfoZ (err 0) Nov 17 15:03:49 eeepc1104 kernel: [43799.327297] hello: Unknown symbol register_chrdev (err 0) Nov 17 15:03:49 eeepc1104 kernel: [43799.327702] hello: Unknown symbol _D15TypeInfo_Struct6__vtblZ (err 0) Nov 17 15:03:49 eeepc1104 kernel: [43799.328252] hello: Unknown symbol Best regards Michael
Re: Translation of C struct to D
Am 2011-11-16 00:53, schrieb Iain Buclaw: Rather than using toStringz, you should be able to get by with declaring the register_chrdev function as follows. extern(C) int register_chrdev (uint major, in char *name, file_operations *fops) This yields the following compiler error: Error: cannot implicitly convert expression (DEVICE_NAME) of type char[] to char* If I try to cast with register_chrdev(0, (char*)DEVICE_NAME, fops); the following error appears: C style cast illegal, use cast(char*)DEVICE_NAME Best regards Michael
Re: Translation of C struct to D
Jerry thought it would be a good idea to write me on 15.11.2011 05:01 GMT +0100 (CET): This looks like you don't have druntime or phobos linked into your module code. My Makefile looks as follows: # D compiler DC := gdc # D objects DOBJS := dinterface.o ifneq ($(MAKE_KBUILD),) # kbuild part of makefile obj-$(CONFIG_HELLO) := hello.o hello-y += $(DOBJS) else # normal part of makefile KERNELDIR := /lib/modules/$(shell uname -r)/build all: $(DOBJS) $(MAKE) -C $(KERNELDIR) M=$(shell pwd) CONFIG_HELLO=m MAKE_KBUILD=1 modules clean: $(MAKE) -C $(KERNELDIR) M=$(shell pwd) MAKE_KBUILD=1 clean %.o: %.d $(DC) -c $ -o $@ endif Is there something missing? Does the original C example work for you? Yes, it works, and also the Hello World module in D from the other webpage works.
Translation of C struct to D
Hi!
I currently try to create a simple linux driver (for test purposes) just
like in [1] in D based on [2]. The main difficulty is to call
register_chrdev. It expects an argument fops of type file_operations
which can look like that in C:
static struct file_operations fops = {
.read = device_read,
.write = device_write,
.open = device_open,
.release = device_release
};
device_read and so on are functions. Originally, file_operations has
much more fields and it's possible to omit unused fields.
What I tried so far: I declared register_chrdev as follows:
extern (C):
int register_chrdev (uint major, char *name, file_operations *fops);
My try for the translation of file_operations looks like that:
struct file_operations {
int function() open;
int function() release;
};
In init_module() I have the following code:
char[] DEVICE_NAME = dtestdev;
file_operations fops;
fops.open = device_open;
fops.release = device_close;
Major = register_chrdev(0, std.string.toStringz(DEVICE_NAME), fops);
The code compiles with some warnings, and if I try to insert it into the
kernel, I get some messages in the kernel log.
WARNING: _D3std6string9toStringzFAaZPa [./hello.ko] undefined!
WARNING: _Dmodule_ref [./hello.ko] undefined!
WARNING: _D15TypeInfo_Struct6__vtblZ [./hello.ko] undefined!
WARNING: register_chrdev [./hello.ko] undefined!
WARNING: _D3std6string12__ModuleInfoZ [./hello.ko] undefined!
Nov 14 21:12:39 eeepc1104 kernel: [17127.068990] hello: Unknown symbol
_D3std6string12__ModuleInfoZ (err 0)
Nov 14 21:12:39 eeepc1104 kernel: [17127.069613] hello: Unknown symbol
register_chrdev (err 0)
Nov 14 21:12:39 eeepc1104 kernel: [17127.070462] hello: Unknown symbol
_D15TypeInfo_Struct6__vtblZ (err 0)
Nov 14 21:12:39 eeepc1104 kernel: [17127.071359] hello: Unknown symbol
_Dmodule_ref (err 0)
Nov 14 21:12:39 eeepc1104 kernel: [17127.072352] hello: Unknown symbol
_D3std6string9toStringzFAaZPa (err 0)
Any help greatly appreciated.
Greetings
Michael
[1] http://tldp.org/LDP/lkmpg/2.6/html/lkmpg.html#AEN680
[2]
http://iainbuclaw.wordpress.com/2010/05/22/writing-a-linux-kernel-module-in-d/
