This function writes a comment to the SPK file associated to the ephemeris descriptor eph. The comment is a null-terminated string of characters pointed to by comment. This function cannot be called after writing a segment to the SPK file (i.e. after calling any of the writeph_spkN_seq_write or writeph_spkN_par_reserve functions), otherwise it will fail.

The following example adds a comment to the new ephemeris file ephemeris.bsp

USE, INTRINSIC :: ISO_C_BINDING
use calceph
TYPE(C_PTR) :: weph

weph = writeph_spk_create("ephemeris.bsp"//C_NULL_CHAR, "asteroid_1"//C_NULL_CHAR)
if (C_ASSOCIATED(weph)) then

     ret = writeph_comment(weph, "Created by ..."//C_NULL_CHAR)
     ret = writeph_comment(weph, "Date  ..."//C_NULL_CHAR)

     ! ... compute and write to weph ...

     call writeph_close(weph)
endif