Determines the lowest virtual address that is not used with the
program.
Format
#include <stdlib.h>
void *brk (unsigned long int addr);
Argument
- addr
- The lowest address, which the function rounds up to the next
multiple of the page size. This rounded address is called the
break address.
Description
An address that is greater than or equal to the break address
and less than the stack pointer is considered to be outside the
program's address space. Attempts to reference it will cause access
violations.
When a program is executed, the break address is set to the
highest location defined by the program and data storage areas.
Consequently, brk is needed only by programs that have growing data
areas.
Return Values
| n | The new break address. |
| (void *)(-1) | Indicates that the
program is requesting too much memory. errno and vaxc$errno are
updated. |
Restriction
Unlike other C library implementations, the DEC C RTL memory allocation functions (such as malloc)
do not rely on brk or sbrk to manage the program heap space.
Consequently, on OpenVMS systems, calling brk or sbrk can interfere
with memory allocation routines. The brk and sbrk functions are
provided only for compatibility purposes.
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