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Dynamic link

libpointer_delete >>

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libpointer

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Creates an C pointer object usuable in Nelson.

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Syntax

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ptr = libpointer()

ptr = libpointer(datatype)

ptr = libpointer(datatype, value)

Input argument

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datatype

a string: data type.

value

a nelson variable compatible with datatype.

Output argument

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ptr

a libpointer handle.

Description

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This is an advanced feature to manipulate C pointers.

ptr = libpointer() creates an NULL pointer.

Examples

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p = libpointer('int8Ptr', int8([3 4]));
p.isNull()
p.DataType
p.Value

NLSDYNAMIC_LINK_IMPEXP double *multiplicationDoubleByReference(double *x)
{
    *x *= 2;
    return x;
}

x = 133.3;
xPtr = libpointer('doublePtr', x);
path_ref = modulepath('dynamic_link', 'builtin');
lib = dlopen(path_ref);
f = dlsym(lib, 'multiplicationDoubleByReference', 'libpointer', {'doublePtr'});
[r1, r2] = dlcall(f, xPtr);
r2
% r1 is an libpointer of type '' (voidPointer) and it need to be change type and size.
r1.setdatatype('doublePtr');
r1.reshape(1, 1);
get(r1)

See also

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C/Nelson equivalent data types, isNull, libpointer.reshape, libpointer.setdatatype.

History

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Version	Description
1.0.0	initial version

Author

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Allan CORNET