Runtime Library

The DQ runtime library provides the low-level services that ordinary programs use implicitly or through standard modules.

Implicit sys

Most non-RTL modules automatically receive the public interface of rtl/sys. That module reexports:

Module	Purpose
rtl/rtlint	low-level runtime intrinsics and type helpers
rtl/exception	Exception, raise, runtime error support, backtraces
rtl/mem	raw memory allocation and memory block helpers
rtl/prgargs	process argument access

It also provides:

function Exit(status : int)

Use dq-comp --no-use-sys only for special low-level code that does not want the implicit merged runtime symbols.

Memory Helpers

Raw memory helpers are available through the implicit runtime interface:

function MemAlloc(allocbytes : int, zeromem : bool = false) -> pointer
function MemFree(memptr : pointer)
function MemFreeRef(memptrvar : ref pointer)
function MemCopy(dest : pointer, src : pointer, size : uint)
function MemSet(dest : pointer, value : int, size : uint)

Prefer normal DQ values, dynamic arrays, strings, and new/delete for ordinary programming. Use these helpers for C interop, buffers, and low-level runtime work.

var p : ^int = ^int(MemAlloc(SizeOf(int), true))
p^ = 123
MemFreeRef(p)  // frees and sets p to null

Program Arguments

The process argument helpers are:

function ArgCount() -> int
function ArgStr(i : int) -> ^cchar

ArgStr(i) returns null for an out-of-range index.

Exceptions And Backtraces

Exception carries a message and a captured backtrace.

try:
    raise Exception("bad input: {}", [name])
except e:
    PrintLn("error: {}", [e.message])
    e.PrintBacktrace()
endtry

For source-line backtraces, compile with debug info and without optimization:

dq-comp -g -O0 app.dq

dq-run app.dq uses those flags by default when no compiler options are passed.