foreign-c-libraries/retropikzel/file-append.scm

22 lines
843 B
Scheme

(define-c-library libc '("stdio.h") #f ())
(define-c-procedure c-fopen libc 'fopen 'pointer '(pointer pointer))
(define-c-procedure c-fwrite libc 'fwrite 'int '(pointer int int pointer))
(define-c-procedure c-fclose libc 'fclose 'int '(pointer))
(define mode-cbv (string->c-bytevector "a"))
(define (with-append-to-file path thunk)
(let* ((path-cbv (string->c-bytevector path))
(file-cbv (c-fopen path-cbv mode-cbv))
(output (parameterize ((current-output-port (open-output-string)))
(apply thunk '())
(get-output-string (current-output-port))))
(output-length (string-length output)))
(with-string->c-bytevector
output
(lambda (output-cbv)
(c-fwrite output-cbv 1 output-length file-cbv)))
(c-fclose file-cbv)
(c-bytevector-free path-cbv)))