hi Mark,

that may very well be so, but I'd naively standardize on C/Fortran behaviour (but that's probably my physicist bias)

on my platform, the following piece of C-code:

$ cat test_cmath.c
#include <complex.h>
#include <stdio.h>

int main(int argc, char** argv)
{
  complex c = casinh(-2*I);
  printf("asinh(-2j) = %g + %gi\n", creal(c), cimag(c));
  return 0;
}
/* EOF */

gives:
$ ./a.out 
asinh(-2j) = -1.31696 + -1.5708i

cheers,
sebastien.