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StrToUInt64

function StrToUInt64(S: string): UInt64;

Example​

procedure ScriptEvent(var Value: variant);
begin
  Value := StrToUInt64('4294967296');
end;

Usage​

StrToUInt64 parses text as an unsigned 64-bit integer and raises when conversion fails.

Parameters

NameTypeDescription
SstringUnsigned decimal or $/0x hexadecimal integer text. Decimal/grouping separators and currency syntax are invalid.

Returns

A UInt64 in the range 0..18446744073709551615.

Errors

Malformed, negative, partial or out-of-range input raises EConvertError and stops the script unless handled. StrToUInt64Def provides a fallback form.

Usage notes

Use this routine only when the receiving field and subsequent calculations preserve UInt64. Casting the result into a signed type or a variant path without unsigned support can lose the upper half of the range.

Additional Technical Info​

StrToUInt64 converts decimal or Delphi-style hexadecimal text into an unsigned 64-bit value. It supports values above signed Int64 maximum and raises when the input is invalid, negative or greater than 18446744073709551615.

The example is source-reviewed and is not executed by the documentation workflow.

Implementation

With PascalScript 64-bit support enabled, runtime dispatch case 45 reads the script ANSI string, converts it to a Delphi string and calls installed System.SysUtils.StrToUInt64. The Delphi terminal invokes intrinsic Val with a UInt64 destination and raises EConvertError whenever Val reports an error.

Edge cases and quirks

  • Negative decimal values do not fit the unsigned destination and fail rather than wrapping.
  • The maximum UInt64 decimal value succeeds; adding one exceeds the destination and fails.
  • A hexadecimal input can represent all 64 bits without becoming negative because the destination itself is unsigned.
  • The full token must convert. Fractional text, grouping characters and trailing junk are invalid.
  • Free Pascal documents additional radix-prefix and whitespace details. Those are not proof of the installed Delphi terminal's accepted grammar; Velox follows Delphi Val through System.SysUtils.StrToUInt64.
  • The function is conditionally registered only when PascalScript has 64-bit integer support. That support is enabled in the reviewed Velox build.

Side effects

None.

Performance and concurrency

Linear in input length with no locale lookup, shared state or I/O.

Related entries

External references

Created 2026-07-15