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Inc

// Generated Code Library declaration:
procedure Inc;

// Effective call contract:
procedure Inc(var X);

Example​

procedure ScriptEvent(var Value: variant);
var
  Counter: Integer;
begin
  Counter := 5;
  Inc(Counter);
  Value := Counter; // 6
end;

Usage​

Increments a supported integer variable by exactly one through Velox scripting's synthetic var parameter.

Parameters

NameTypeDescription
Xsupported integer variable, varValue changed in place. It must be assignable storage, not a literal or calculated expression.

Supported runtime storage types are Byte, ShortInt, Word, SmallInt, Cardinal, Integer, Int64 and UInt64. Unsupported untyped arguments can compile but fail when the value type switch is executed.

Boundary behaviour and quirks

  • Only a step of one is available. Velox's Inc(X, N) overload is not available.
  • Velox scripting.inc explicitly compiles this runtime with range and overflow checks off, overriding the enclosing project setting. Every supported fixed-width type wraps at its boundary: Inc(High(Byte)) becomes 0, Inc(High(Integer)) becomes Low(Integer), and Inc(High(UInt64)) becomes 0.
  • The Cardinal branch passes through signed SetInt, but unchecked conversions preserve the low 32-bit pattern; values above High(Integer) remain usable until the Cardinal itself wraps.
  • btEnum, Char and Variant are absent from the runtime switch. Do not infer Velox's wider ordinal support from the name.

Additional Technical Info​

Inc adds exactly one to a mutable PascalScript integer variable. The generated declaration is incomplete: the compiler adds a required untyped var X parameter after creating the displayed declaration.

This is a PascalScript runtime helper, not Delphi's full intrinsic contract. It has no second increment-amount argument and does not support pointers, characters, enumerations or Variants through this registered path. The example is fictional and source-reviewed only.

Implementation

  1. The compiler adds the synthetic in/out parameter.
  2. Runtime Inc_ resolves that parameter by reference.
  3. It switches on the exact integer base type, adds one and writes through a type-specific stack setter.
  4. Any unhandled base type returns failure, which PascalScript reports as a call/type error.

This external helper is separate from the cm_inc bytecode which the compiler emits internally for a for loop counter.

Concurrency and side effects

X is mutated in place without a lock or interlocked instruction. It is unsuitable as a concurrency-safe shared counter. Check the boundary explicitly when wraparound is not intended.

Related entries

  • Dec subtracts one using the corresponding runtime helper.
  • GetAndInc returns a Variant's previous Integer value and then mutates it, also without atomicity.

External references

Created 2026-07-15