NAME

SYNOPSIS

DCCallVM *
dcNewCallVM(DCsize size);

void
dcFree(DCCallVM * vm);

void
dcMode(DCCallVM * vm, DCint mode);

void
dcReset(DCCallVM * vm);

void
dcArgBool(DCCallVM * vm, DCbool arg);

void
dcArgChar(DCCallVM * vm, DCchar arg);

void
dcArgShort(DCCallVM * vm, DCshort arg);

void
dcArgInt(DCCallVM * vm, DCint arg);

void
dcArgLong(DCCallVM * vm, DClong arg);

void
dcArgLongLong(DCCallVM * vm, DClonglong arg);

void
dcArgFloat(DCCallVM * vm, DCfloat arg);

void
dcArgDouble(DCCallVM * vm, DCdouble arg);

void
dcArgPointer(DCCallVM * vm, DCpointer arg);

DCvoid
dcCallVoid(DCCallVM * vm, DCpointer funcptr);

DCbool
dcCallBool(DCCallVM * vm, DCpointer funcptr);

DCchar
dcCallChar(DCCallVM * vm, DCpointer funcptr);

DCshort
dcCallShort(DCCallVM * vm, DCpointer funcptr);

DCint
dcCallInt(DCCallVM * vm, DCpointer funcptr);

DClong
dcCallLong(DCCallVM * vm, DCpointer funcptr);

DClonglong
dcCallLongLong(DCCallVM * vm, DCpointer funcptr);

DCfloat
dcCallFloat(DCCallVM * vm, DCpointer funcptr);

DCdouble
dcCallDouble(DCCallVM * vm, DCpointer funcptr);

DCpointer
dcCallPointer(DCCallVM * vm, DCpointer funcptr);

void
dcArgF(DCCallVM * vm, const DCsigchar * signature, ...);

void
dcVArgF(DCCallVM * vm, const DCsigchar * signature, va_list args);

void
dcCallF(DCCallVM * vm, DCValue * result, DCpointer funcptr, const DCsigchar * signature, ...);

void
dcVCallF(DCCallVM * vm, DCValue * result, DCpointer funcptr, const DCsigchar * signature, va_list args);

DESCRIPTION

In other words, instead of calling a function directly, the dyncall library provides a mechanism to push the function parameters manually and to issue the call afterwards.

Since the idea behind this concept is similar to call dispatching mechanisms of virtual machines, the object that can be dynamically loaded with arguments, and then used to actually invoke the call, is called CallVM. It is possible to change the calling convention used by the CallVM at run-time. Due to the fact that nearly every platform comes with one or more distinct calling conventions, the dyncall library project intends to be a portable and open-source approach to the variety of compiler-specific binary interfaces, platform specific subtleties, and so on...

dcNewCallVM() creates a new CallVM object, where size specifies the max size of the internal stack that will be allocated and used to bind the arguments to. Use dcFree() to destroy the CallVM object.

dcMode() sets the calling convention to use. See dyncall.h for a list of available modes. Note that some mode/platform combinations don't make any sense (e.g. using a PowerPC calling convention on a MIPS platform) and are silently ignored.

dcReset() resets the internal stack of arguments and prepares it for a new call. This function should be called after setting the call mode (using dcMode), but prior to binding arguments to the CallVM (except for when setting mode DC_SIGCHAR_CC_ELLIPSIS_VARARGS, which is used prior to binding varargs of variadic functions). Use it also when reusing a CallVM, as arguments don't get flushed automatically after a function call invocation. Note: you should also call this function after initial creation of the a CallVM object, as dcNewCallVM doesn't do this, implicitly.

dcArgBool(), dcArgChar(), dcArgShort(), dcArgInt(), dcArgLong(), dcArgLongLong(), dcArgFloat(), dcArgDouble() and dcArgPointer() are used to bind arguments of the named types to the CallVM object. Arguments should be bound in left to right order regarding the C function prototype.

dcCallVoid(), dcCallBool(), dcCallChar(), dcCallShort(), dcCallInt(), dcCallLong(), dcCallLongLong(), dcCallFloat(), dcCallDouble() and dcCallPointer() call the function with the bound arguments and returning the named type, where funcptr is a pointer to the function to call. After the invocation of the function call, the argument values are still bound to the CallVM and a second call using the same arguments can be issued. Call reset() to clear the internal argument stack.

dcArgF(), dcVArgF(), dcCallF() and dcVCallF() can be used to bind arguments in a printf-style call, using a signature string encoding the argument types and return type. The former 2 only bind the arguments to the vm object (and ignore return types specified in the signature), whereas the latter two issue a call to the given function pointer, afterwards. The return value will be stored in result. The signature string also features calling convention mode selection. For information about the signature format, refer to the dyncall manual in PDF format.

EXAMPLE

	double sqrt(double x);

Using the dyncall library, this function would be called as follows:

	double r;
	DCCallVM* vm = dcNewCallVM(4096);
	dcMode(vm, DC_CALL_C_DEFAULT);
	dcReset(vm);
	dcArgDouble(vm, 4.2373);
	r = dcCallDouble(vm, (DCpointer)&sqrt);
	dcFree(vm);

CONFORMING TO

SEE ALSO

AUTHORS