Q58933: Cannot Allocate More Than 64K with Calloc()

Article: Q58933
Product(s): See article
Version(s): 5.10   | 5.10
Operating System(s): MS-DOS | OS/2
Keyword(s): ENDUSER | s_quickc s_quickasm | mspl13_c
Last Modified: 8-MAR-1990

Although calloc() takes two unsigned integers as parameters, it does
not allocate more than 64K. Calloc() determines the size you are
attempting to allocate by multiplying the two arguments. If the size
is greater than 64K, it will return NULL.

The confusion typically arises because, with malloc(), it is
impossible to ask for more than 64K due to the size of the argument
malloc() takes. Malloc() takes an unsigned int as an argument;
therefore, the largest number you can pass it cannot be greater than
64K. This is not the case with calloc() -- so one might make the
assumption that you COULD allocate more than 64K with calloc(). This
is simply not the case.

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