#include <sys/nearptr.h> int __djgpp_nearptr_enable(void);
This function enables "near pointers" to be used to access the DOS
memory arena. Sort of. When you call this function, it will return
nonzero if it has successfully enabled near pointers. If so, you must
add the value __djgpp_conventional_base to the linear address
of the physical memory. For example:
if (__djgpp_nearptr_enable())
{
short *screen = (short *)(__djgpp_conventional_base + 0xb8000);
for (i=0; i<80*24*2; i++)
screen[i] = 0x0720;
__djgpp_nearptr_disable();
}
The variable __djgpp_base_address contains the linear base
address of the application's data segment. You can subtract this
value from other linear addresses that DPMI functions might return
in order to obtain a near pointer to those linear regions as well.
If using the Unix-like sbrk algorithm, near pointers are only valid
until the next malloc, system, spawn*, or
exec* function call, since the linear base address of the
application may be changed by these calls.
WARNING: When you enable near pointers, you disable all the protection that the system is providing. If you are not careful, your application may destroy the data in your computer. USE AT YOUR OWN RISK!
Returns 0 if near pointers are not available, or nonzero if they are.
not ANSI, not POSIX
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