Hi All,

tango.text.convert.Format provides a nice function to convert anything to string.

It works perfect except the argument is a pointer type.
It will print the address of a pointer instead of its value

For instance: --------------------------------
int* i = new int;
*i = 10;
Format.convert("{}", i); // <- the address of the pointer
----------------------------------------------

How to let it print the value instead of the address?
Because I wanna write a dump function to dump the value of any data type (also void, null)




-- 
Xu, Qian (stanleyxu)
 http://stanleyxu2005.blogspot.com

Qian Xu wrote:
> Hi All,
> 
> tango.text.convert.Format provides a nice function to convert anything to string.
> 
> It works perfect except the argument is a pointer type.
> It will print the address of a pointer instead of its value
> 
> For instance: --------------------------------
> int* i = new int;
> *i = 10;
> Format.convert("{}", i); // <- the address of the pointer
> ----------------------------------------------
> 
> How to let it print the value instead of the address?
> Because I wanna write a dump function to dump the value of any data type (also void, null)

Check if the variable is a pointer, and if yes, dereference it:

alias typeof(i) T;
static if (is(T T2 : T2*)) {
	T2 i2 = *i;
	Format.convert("{}", i2);
} else {
	Format.convert("{}", i);
}

Qian Xu schrieb:
> Hi All,
> 
> tango.text.convert.Format provides a nice function to convert anything to string.
> 
> It works perfect except the argument is a pointer type.
> It will print the address of a pointer instead of its value
> 
> For instance: --------------------------------
> int* i = new int;
> *i = 10;
> Format.convert("{}", i); // <- the address of the pointer
> ----------------------------------------------
> 
> How to let it print the value instead of the address?
> Because I wanna write a dump function to dump the value of any data type
> (also void, null)
> 
> 
> 
> 

This is not really an exact answer to your question... :)
It seems you want to output trace information. Stdout (which seems you
are using) is not thread safe and will generate AV/segf if accessed
concurrently.
Specially for printing trace info, there is
tango.util.log.Trace
it is a Stdout replacement that is synchronized, and it also has a
memory() function, that lets you print raw memory as a dump.

grauzone wrote:

> 
> Check if the variable is a pointer, and if yes, dereference it:
> 
> alias typeof(i) T;
> static if (is(T T2 : T2*)) {
> T2 i2 = *i;
> Format.convert("{}", i2);
> } else {
> Format.convert("{}", i);
> }

Hi again,

I cannot compile this code

Qian Xu wrote:
> grauzone wrote:
> 
>> Check if the variable is a pointer, and if yes, dereference it:
>>
>> alias typeof(i) T;
>> static if (is(T T2 : T2*)) {
>> T2 i2 = *i;
>> Format.convert("{}", i2);
>> } else {
>> Format.convert("{}", i);
>> }
> 
> Hi again,
> 
> I cannot compile this code 

What exactly are you doing? What do you want to do? Without knowing this, we can only guess. My first reply to you was also just a guess. I thought maybe you had a templated function, and wanted to dump a templated variable, or so.

Anyway, here's a complete version of my example above. It uses Stdout.formatln instead of Format.convert, but this shouldn't matter at all.

import tango.io.Stdout;

void main() {

    int v = 55;
    int *pv = &v;

    //pv (an int pointer) can be exchanged with v (an int),
    //and it still works
    auto i = pv;

    alias typeof(i) T;
    static if (is(T T2 : T2*)) {
        T2 i2 = *i;
        Stdout.formatln("{}", i2);
    } else {
        Stdout.formatln("{}", i);
    }

}

grauzone wrote:

> mport tango.io.Stdout;
> 
> void main() {
> 
> int v = 55;
> int *pv = &v;
> 
> //pv (an int pointer) can be exchanged with v (an int),
> //and it still works
> auto i = pv;
> 
> alias typeof(i) T;
> static if (is(T T2 : T2*)) {
> T2 i2 = *i;
> Stdout.formatln("{}", i2);
> } else {
> Stdout.formatln("{}", i);
> }
> 
> }


Thanks. Now I understood your code. ^^)