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In computer programming, a callback is a function that is stored as data (a reference) and designed to be called by another function – often back to the original abstraction layer. A function that accepts a callback parameter may be designed to call back before returning to its caller which is known as synchronous or blocking.
A wrapper function is a function (another word for a subroutine) in a software library or a computer program whose main purpose is to call a second subroutine [1] or a system call with little or no additional computation. Wrapper functions simplify writing computer programs by abstracting the details of a subroutine's implementation.
VBA can, however, control one application from another using OLE Automation. For example, VBA can automatically create a Microsoft Word report from Microsoft Excel data that Excel collects automatically from polled sensors. VBA can use, but not create, ActiveX/COM DLLs, and later versions add support for class modules.
Another, less common, use of macros is to do the reverse: to map a sequence of instructions to a macro string. This was the approach taken by the STAGE2 Mobile Programming System , which used a rudimentary macro compiler (called SIMCMP) to map the specific instruction set of a given computer into machine-independent macros.
A foreign function interface (FFI) is a mechanism by which a program written in one programming language can call routines or make use of services written or compiled in another one. An FFI is often used in contexts where calls are made into a binary dynamic-link library .
The call to d->f1() passes a B1 pointer as a parameter. The call to d->f2() passes a B2 pointer as a parameter. This second call requires a fixup to produce the correct pointer. The location of B2::f2 is not in the virtual method table for D. By comparison, a call to d->fnonvirtual() is much simpler: (*
Note that after calling (), we are left with a function that takes a single argument and returns another function, not a function that takes two arguments. In contrast, partial function application refers to the process of fixing a number of arguments to a function, producing another function of smaller arity.
The next program uses a function pointer to invoke one of two functions (sin or cos) indirectly from another function (compute_sum, computing an approximation of the function's Riemann integration). The program operates by having function main call function compute_sum twice, passing it a pointer to the library function sin the first time, and ...