Create an object at a given address: Difference between revisions
Create an object at a given address (view source)
Revision as of 14:11, 21 November 2023
, 6 months ago→{{header|Wren}}: Minor tidy
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Teresa 60
</pre>
=={{header|FutureBasic}}==
<syntaxhighlight lang="futurebasic">
include "NSLog.incl"
local fn DoIt
NSLog( @"Dimension in integer \"x\", but do not assign it a value.\n" )
long x
// Note that the @ (at sign) prefixing x is a pointer to its machine address
NSLog( @"The machine address of x is: %p", @x )
NSLog( @"While x is unassigned, the machine address will contain a garbage value: %ld\n", x )
// Assign x a value of 1234
x = 1234
NSLog( @"When x is assigned a value of %ld, that value will be stored in the machine address: %p", x, @x )
NSLog( @"The machine address now contains the value: %ld\n", x )
// Reassign x a value of 5678
x = 5678
NSLog( @"Wnen x is reassigned the new value %ld, that value will be stored in the existing machine address: %p", x, @x )
NSLog( @"The machine address now contains the value: %ld\n", x )
end fn
fn DoIt
HandleEvents
</syntaxhighlight>
{{output}}
<pre>
Dimension in integer "x", but do not assign it a value.
The machine address of x is: 0x7ffee279bb58
While x is unassigned, the machine address will contain a garbage value: 1099524915200
When x is assigned a value of 1234, that value will be stored in the machine address: 0x7ffee279bb58
The machine address now contains the value: 1234
Wnen x is reassigned the new value 5678, that value will be stored in the existing machine address: 0x7ffee279bb58
The machine address now contains the value: 5678
</pre>
=={{header|Go}}==
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Note that it is not possible to specify the address at which the embedding API function ''wrenSetSlotNewForeign'' allocates new objects and any attempt to allocate a new object at the same address as an old one by juggling with pointers will almost certainly lead to a seg fault. So all we can sensibly do is to change the value of the current object.
<syntaxhighlight lang="
import "./fmt" for Fmt
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<br>
We now embed this in the following C program, compile and run it.
<syntaxhighlight lang="c">/* gcc
#include <stdio.h>
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WrenVM* vm = wrenNewVM(&config);
const char* module = "main";
const char* fileName = "
char *script = readFile(fileName);
WrenInterpretResult result = wrenInterpret(vm, module, script);
Line 1,229 ⟶ 1,272:
Integer object value changed to: 43 but still at address 0x55a56e0f2dd8.
</pre>
=={{header|Z80 Assembly}}==
When writing assembly yourself, you'll know any object's memory location in advance.
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