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A basic example is in the argv argument to the main function in C (and C++), which is given in the prototype as char **argv—this is because the variable argv itself is a pointer to an array of strings (an array of arrays), so *argv is a pointer to the 0th string (by convention the name of the program), and **argv is the 0th character of the ...
The sizes of integer types are defined in Java (int is 32-bit, long is 64-bit), while in C++ the size of integers and pointers is compiler and application binary interface (ABI) dependent within given constraints. Thus a Java program will have consistent behavior across platforms, whereas a C++ program may require adapting for some platforms ...
In addition to support for vectorized arithmetic and relational operations, these languages also vectorize common mathematical functions such as sine. For example, if x is an array, then y = sin (x) will result in an array y whose elements are sine of the corresponding elements of the array x. Vectorized index operations are also supported.
Furthermore, pointers of different sizes can alias accesses to the same memory, causing problems that are unchecked by the compiler. Even when data size and pointer representation match, however, compilers can rely on the non-aliasing constraints to perform optimizations that would be unsafe in the presence of disallowed aliasing.
Java C# Arrays are implicitly direct specializations of Object. They are not unified with collection types. Arrays in C# are implicit specializations of the System.Array class that implements several collection interfaces. Arrays and collections are completely separate with no unification.
Oracle's HotSpot Java Virtual Machine uses an SSA-based intermediate language in its JIT compiler. [29] Microsoft Visual C++ compiler backend available in Microsoft Visual Studio 2015 Update 3 uses SSA [30] SPIR-V, the shading language standard for the Vulkan graphics API and kernel language for OpenCL compute API, is an SSA representation. [31]
The run-time representation of a pointer value is typically a raw memory address (perhaps augmented by an offset-within-word field), but since a pointer's type includes the type of the thing pointed to, expressions including pointers can be type-checked at compile time. Pointer arithmetic is automatically scaled by the size of the pointed-to ...
A long double (eight bytes with Visual C++, sixteen bytes with GCC) will be 8-byte aligned with Visual C++ and 16-byte aligned with GCC. Any pointer (eight bytes) will be 8-byte aligned. Some data types are dependent on the implementation. Here is a structure with members of various types, totaling 8 bytes before compilation: