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IncludeTrailingPathDelimiter

Function IncludeTrailingPathDelimiter( const S : string) : string

Example​

procedure ScriptEvent(var Value: variant);
begin
  Value := IncludeTrailingPathDelimiter('C:\Fictional\Inbound');
  // C:\Fictional\Inbound\
end;

Usage​

IncludeTrailingPathDelimiter appends the platform path delimiter when a path string does not already end with one.

Parameters

NameTypeDescription
Sstring, constDirectory/path text to transform.

Returns

The original text when it already ends in PathDelim; otherwise the original text followed by one PathDelim.

Behaviour

  • 'C:\Folder' becomes 'C:\Folder\' on Windows.
  • 'C:\Folder\' is unchanged.
  • '' becomes '\' on Windows.
  • The result is suitable for simple lexical concatenation only after the base path and suffix have been validated.

Errors

No normal path-content exception is raised. Conversion and allocation failures can propagate.

Usage notes

Check for empty and drive-relative input before calling when those forms are not allowed. This routine is not a path canonicaliser or security boundary.

Additional Technical Info​

IncludeTrailingPathDelimiter returns S with the platform path delimiter appended unless the string already ends in that delimiter. It changes only text and does not create or inspect a directory.

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

Implementation

The Velox wrapper calls installed System.SysUtils.IncludeTrailingPathDelimiter. The RTL copies S, tests High(S) using IsPathDelimiter, and appends PathDelim when the test is false.

Edge cases and quirks

  • The current Windows PathDelim is backslash. A string ending in / is not accepted as already delimited; a backslash is appended, producing a mixed '/\' ending.
  • Empty input becomes the current-drive root syntax '\', not an empty value and not a configured working directory.
  • The function does not collapse duplicates, resolve relative segments, add a drive, convert URL separators or check existence.
  • A drive-relative value such as 'C:' becomes 'C:\', which changes its lexical meaning from current directory on drive C to the drive root.
  • Existing trailing whitespace remains before the appended delimiter.

Side effects

None.

Performance and concurrency

The function copies the input and may append one character. Work is linear in length, with no shared mutable state.

Related entries

External references

Created 2026-07-15