User`s guide

BDOS FUNCTION 98: FREE BLOCKS

Entry Parameters:

Returned Value:

Registers A: Error Flag

H: Physical Error

The Free Blocks function scans all the currently logged-in drives, and for each

drive returns to free space all temporarily-allocated data blocks. A temporarily-allo-

cated data block is a block that has been allocated to a file by a BDOS write

operation but has not been permanently recorded in the directory by a BDOS close

operation. The CCP calls Function 98 when it receives control following a system

warm start. Be sure to close your file, particularly any file you have written to, prior

to calling Function 98.

In the nonbanked version of CP/M 3, Function 98 frees only temporarily allocated

blocks for systems that request double allocation vectors in GENCPM.

Upon return, register A is set to zero if Function 98 is successful. If a physical

error is encountered, the Free Blocks function performs different actions depending

on the BDOS error mode (see Function 45). If the BDOS error mode is in the default

mode, a message identifying the error is displayed at the console and the calling

program is terminated. Otherwise, the Free Blocks function returns to the calling

program with register A set to OFFH and register H set to the following physical

error code:

04 : Invalid drive error

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BDOS Function Calls CP/M 3 Programmers Guide