Q23905: Initial Memory Allocation of C Programs

Article: Q23905
Product(s): See article
Version(s): 4.00 5.00 5.10
Operating System(s): MS-DOS
Keyword(s): ENDUSER | DGROUP 64K | mspl13_c
Last Modified: 15-JAN-1990

Question:

I want to make a program "terminate and stay resident." It is a very
short program with only 4K of data and about 2K of code. However, when
I execute the program to make it resident and do a CHKDSK, it seems to
occupy about 70K. Why does it take up so much space?

Response:

The linker normally allocates all of memory to a program. You can use
the /CP switch to adjust the allocation down. If you specify an amount
less than the minimum allocation, the maximum allocation will default
to that minimum, so link with /CP:1.

You can also use the /max <MinimumAllocationInHexParagraphs> option of
the EXEMOD.EXE utility to adjust the maximum allocation of a program.

Microsoft C was not designed for writing memory resident software.
Although it is possible, you also may need to make modifications to
the start-up code. Be cautious about what functions you use and what
DOS functions are called.

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