The alternative name call/cc is available in Racket*, Gauche, Gambit, Chicken, Bigloo, Guile*, Kawa, SISC, Chibi+, Chez*, Vicare*, Larceny*, Ypsilon*, Mosh*, IronScheme*, NexJ, STKlos, KSi, SigScheme, TinyScheme, S7, XLisp, XLisp, Rep, Schemik, Elk, UMB, Oaklisp, Llava, SXM, Sizzle, Spark, Inlab, Owl Lisp, Scheme 9.
It is not available in MIT, Scheme48/scsh, SCM, Shoe, Dream, RScheme, BDC, VX, FemtoLisp, Dfsch.
[*] Required by R6RS
[+] Required by R7RS-small
The following Schemes that support call/cc return different error messages from (call-with-current-continuation 32) and (call/cc 32), implying that they are distinct procedures: Chicken, Bigloo, Guile*, Chez, Vicare, Ypsilon*, XLisp, Oaklisp*.
[*] Error messages differ only in a hex address for the procedure or opcode