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StrToInt

function StrToInt(S: string): LongInt;

Example​

procedure ScriptEvent(var Value: variant);
begin
  Value := StrToInt('2048');  // 2048
end;

Usage​

StrToInt parses a signed LongInt through Velox scripting, returning -1 when the text is invalid.

Parameters

NameTypeDescription
SstringText for a signed 32-bit integer. Velox Val accepts signed decimal and the $ or 0x hexadecimal prefixes; decimal and thousands separators are not valid for an integer destination.

Returns

The parsed value in the LongInt range -2147483648..2147483647. It returns the sentinel -1 whenever Val reports an error.

Errors

Conversion errors are swallowed and represented as -1. Other failures, such as allocation/runtime faults while moving the script string, are not part of that sentinel contract.

Usage notes

Prefer StrToIntDef with a domain-impossible fallback when validation is required. Even then, the fallback can collide with valid data if chosen from the accepted range. Use StrToInt64 when 64-bit range and exception-based failure are required.

Additional Technical Info​

StrToInt parses a signed 32-bit LongInt with Pascal's intrinsic Val conversion. The Velox PascalScript runtime has a material compatibility quirk: malformed or out-of-range input returns -1 instead of raising the EConvertError documented for Delphi and Free Pascal SysUtils.StrToInt.

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

Implementation

PascalScript installs StrToInt as a standard compiler function. Runtime dispatch case 1 passes the script's ANSI string to the modified PascalScript uPSUtils.StrToInt, which converts it to a Delphi string and calls intrinsic System.Val with a LongInt destination. A zero error position returns the parsed value; any non-zero error position is discarded and replaced by -1.

This path does not call Delphi System.SysUtils.StrToInt despite sharing its public name.

Edge cases and quirks

  • -1 is both a valid parsed value and the failure sentinel. The caller cannot distinguish StrToInt('-1') from StrToInt('invalid') by examining the result.
  • Overflow and underflow are treated like syntax errors and also return -1.
  • Parsing is whole-value: a valid numeric prefix followed by an invalid character does not return the prefix.
  • Integer parsing is locale-independent. Decimal points, grouping characters and currency symbols are errors.
  • The Delphi Val terminal documents decimal plus $ and 0x hexadecimal forms. Free Pascal Val additionally documents binary and octal prefixes; those are dialect features and are not evidence that the current Delphi terminal accepts them.
  • Hexadecimal input is converted into the 32-bit destination's representation. Use explicit range-aware logic when a text protocol defines unsigned values.

Side effects

None.

Performance and concurrency

Linear in the short input string with no locale lookup, I/O or shared mutable state.

Related entries

  • StrToIntDef lets the caller choose the failure value.
  • StrToInt64 uses Delphi's 64-bit exception-raising routine rather than this modified 32-bit terminal.
  • StrToUInt64 parses the unsigned 64-bit range.

External references

  • Free Pascal System.Val - compatibility reference for the intrinsic conversion model; its extra radix forms are not the Delphi contract.
  • Embarcadero System.Val - the Delphi intrinsic reached by the modified PascalScript terminal.
Created 2026-07-15