Column Information Routines

1

Get information about an existing ASCII table column. A null pointer may be given for any of the output parameters that are not needed.  

int fits_get_acolparms / ffgacl
    (fitsfile *fptr, int colnum, > char *ttype, long *tbcol,
     char *tunit, char *tform, double *scale, double *zero,
     char *nulstr, char *tdisp, int *status)

2

Get information about an existing binary table column. DATATYPE is a character string which returns the datatype of the column as defined by the TFORMn keyword (e.g., 'I', 'J','E', 'D', etc.). In the case of an ASCII character column, typecode will have a value of the form 'An' where 'n' is an integer expressing the width of the field in characters. For example, if TFORM = '160A8' then ffgbcl will return typechar='A8' and repeat=20. All the returned parameters are scalar quantities. A null pointer may be given for any of the output parameters that are not needed.  

  int fits_get_bcolparms / ffgbcl
      (fitsfile *fptr, int colnum, > char *ttype, char *tunit,
       char *typechar, long *repeat, double *scale, double *zero,
       long *nulval, char *tdisp, int  *status)

3

Return optimal number of rows to read or write at one time for maximum I/O efficiency. Refer to the ``Optimizing Code'' section in Chapter 5 for more discussion on how to use this routine.  

  int fits_get_rowsize / ffgrsz
      (fitsfile *fptr, long *nrows, *status)

4

Define the zero indexed byte offset of the 'heap' measured from the start of the binary table data. By default the heap is assumed to start immediately following the regular table data, i.e., at location NAXIS1 x NAXIS2. This routine is only relevant for binary tables which contain variable length array columns (with TFORMn = 'Pt'). This routine also automatically writes the value of theap to a keyword in the extension header. This routine must be called after the required keywords have been written (with ffphbn) and after the table structure has been defined (with ffbdef) but before any data is written to the table.  

  int fits_write_theap / ffpthp
      (fitsfile *fptr, long theap, > int *status)