SWI-Prolog -- swritef/3

Documentation
- Reference manual
  - Built-in Predicates
    - Formatted Write
      - Writef
        
        writef/1
        
        writef/2
        
        swritef/3
        
        swritef/2
- Packages

Availability::- use_module(library(writef)).(can be autoloaded)

Source

[deprecated]swritef(-String, +Format, +Arguments)

Equivalent to writef/2, but “writes” the result on String instead of the current output stream. Example:

?- swritef(S, '%15L%w', ['Hello', 'World']).

S = "Hello          World"