Table of Contents

Note: This API call is for DOS and Win16 personality only. Use Family API for portability.

2018/09/07 05:04 · prokushev · 0 Comments

Int 21H, AH=49H

Version

2 and higher

Brief

FREE MEMORY

Family API

Input

AH = 49h
ES = segment of block to free

Return

CF clear if successful
CF set on error
    AX = error code (07h,09h) (see #01680 at AH=59h/BX=0000h)

Notes

apparently never returns an error 07h, despite official docs; DOS 2.1+ code contains only an error 09h exit

DOS 2.1-6.0 does not coalesce adjacent free blocks when a block is freed, only when a block is allocated or resized

the code for this function is identical in DOS 2.1-6.0 except for calls to start/end a critical section in DOS 3.0+

See also

AH=48h,AH=4Ah

Note

Text based on Ralf Brown Interrupt List Release 61

2018/09/04 17:23 · prokushev · 0 Comments