qa.hlp (Table of Contents; Topic list)
Int 21H Function 4AH
   Summary  Notes  Example  Back
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▀ This function modifies the size of a memory block that was previously
  allocated with a call to Int 21H Function 48H.
 
▀ If the program is requesting an increase in the size of an allocated
  block, and this function fails, the maximum possible size for the speci-
  fied block is returned in register BX. The program can use this value to
  determine whether it should terminate, or continue in a degraded fashion
  with less memory.
 
▀ A program that uses EXEC (Int 21H Function 4BH) to load and execute a
  child program must call this function first, passing the address of its
  own PSP in register ES and the amount of memory needed for its own code,
  data, and stacks in register BX.
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