Initialization

CALL FFINIT (NW)

This subroutine initializes the FFREAD package.

If any keys had been previously specified, they are erased with all associated information. The values for the input and output logical units are reset to their default values, which direct them to the terminal or command file/batch log. The significant key size is reset to its default value of 4.

The integer argument NW specifies the number of words the user has allocated to the COMMON /CFREAD/, in which FFREAD keeps all its information. If NW = 0, the default size is large enough to hold 50 keys of the default length (on all machines). If a larger number of keys is required, the user must do the following:

• Define CFREAD to be of appropriate size by including a statement like

   
          COMMON /CFREAD/ SPACE(1000)
  

  in his programme.

• Call FFINIT with the proper size, i.e. for the above example:

          CALL FFINIT (1000)
  

  The calculation of the required size for a given number of keys is as follows:

• divide the required key size by the number of characters per word (as returned by FFGET with option 'NCHW') and round, if not integer, to the next higher integer
• add to this a fixed overhead of three words per key
• multiply by the number of keys needed
• add a fixed overhead of 41 words for FFREAD's internal management.