etext := ldr.Lookup("runtime.etext", 0)
		edata := ldr.Lookup("runtime.edata", 0)
		end := ldr.Lookup("runtime.end", 0)
		ldr.SetSymExtname(etext, "runtime.etext")
		ldr.SetSymExtname(edata, "runtime.edata")
		ldr.SetSymExtname(end, "runtime.end")
		ctxt.xdefine("_etext", ldr.SymType(etext), ldr.SymValue(etext))
		ctxt.xdefine("_edata", ldr.SymType(edata), ldr.SymValue(edata))

	if base, _, _ := findObject(uintptr(p), 0, 0); base != 0 {
		return base
	}

	// data or bss
	for _, datap := range activeModules() {
		if datap.data <= uintptr(p) && uintptr(p) < datap.edata {
			return datap.data
		}
		if datap.bss <= uintptr(p) && uintptr(p) < datap.ebss {
			return datap.bss
		}
	}

	return 0

	}
	if start > firstmoduledata.bss {
		start = firstmoduledata.bss
	}
	if end < firstmoduledata.enoptrdata {
		end = firstmoduledata.enoptrdata
	}
	if end < firstmoduledata.edata {
		end = firstmoduledata.edata
	}
	if end < firstmoduledata.enoptrbss {
		end = firstmoduledata.enoptrbss
	}
	if end < firstmoduledata.ebss {
		end = firstmoduledata.ebss
	}
	size := alignUp(end-start, _PageSize)

		cgoCheckBits(src, typ.GCData, off, size)
		return
	}

	// The type has a GC program. Try to find GC bits somewhere else.
	for _, datap := range activeModules() {
		if cgoInRange(src, datap.data, datap.edata) {
			doff := uintptr(src) - datap.data
			cgoCheckBits(add(src, -doff), datap.gcdatamask.bytedata, off+doff, size)
			return
		}
		if cgoInRange(src, datap.bss, datap.ebss) {
			boff := uintptr(src) - datap.bss

			if cgoIsGoPointer(pp) && !isPinned(pp) {
				panic(errorString(msg))
			}
		}
		return
	}

	for _, datap := range activeModules() {
		if cgoInRange(p, datap.data, datap.edata) || cgoInRange(p, datap.bss, datap.ebss) {
			// We have no way to know the size of the object.
			// We have to assume that it might contain a pointer.
			panic(errorString(msg))
		}

	// TODO(mwhudson): dump datamask etc from all objects
	// data segment
	dumpint(tagData)
	dumpint(uint64(firstmoduledata.data))
	dumpmemrange(unsafe.Pointer(firstmoduledata.data), firstmoduledata.edata-firstmoduledata.data)
	dumpfields(firstmoduledata.gcdatamask)

	// bss segment
	dumpint(tagBSS)
	dumpint(uint64(firstmoduledata.bss))

Tornando al precedente esempio, **FastAPI**:

* Validerà che esiste un `item_id` nel percorso delle richieste `GET` e `PUT`.
* Validerà che `item_id` sia di tipo `int` per le richieste `GET` e `PUT`.
    * Se non lo è, il client vedrà un errore chiaro e utile.
* Controllerà se ci sia un parametro opzionale chiamato `q` (per esempio `http://127.0.0.1:8000/items/foo?q=somequery`) per le richieste `GET`.

	filetab      []byte
	pctab        []byte
	pclntable    []byte
	ftab         []functab
	findfunctab  uintptr
	minpc, maxpc uintptr

	text, etext           uintptr
	noptrdata, enoptrdata uintptr
	data, edata           uintptr
	bss, ebss             uintptr
	noptrbss, enoptrbss   uintptr
	covctrs, ecovctrs     uintptr
	end, gcdata, gcbss    uintptr
	types, etypes         uintptr
	rodata                uintptr

	// due to external linking.
	for datap := &firstmoduledata; datap != nil; datap = datap.next {
		if datap.noptrdata <= uintptr(p) && uintptr(p) < datap.enoptrdata ||
			datap.data <= uintptr(p) && uintptr(p) < datap.edata ||
			datap.bss <= uintptr(p) && uintptr(p) < datap.ebss ||
			datap.noptrbss <= uintptr(p) && uintptr(p) < datap.enoptrbss {
			return true
		}
	}
	return false
}

		return int(divRoundUp(bytes, rootBlockBytes))
	}

	work.nDataRoots = 0
	work.nBSSRoots = 0

	// Scan globals.
	for _, datap := range activeModules() {
		nDataRoots := nBlocks(datap.edata - datap.data)
		if nDataRoots > work.nDataRoots {
			work.nDataRoots = nDataRoots
		}

		nBSSRoots := nBlocks(datap.ebss - datap.bss)
		if nBSSRoots > work.nBSSRoots {
			work.nBSSRoots = nBSSRoots
		}
	}