newlib-cygwin/newlib/libc/sys/linux/brk.c

42 lines
848 B
C

/* libc/sys/linux/brk.c - Change data segment size */
/* Written 2000 by Werner Almesberger */
#include <stddef.h> /* for NULL */
#include <sys/types.h>
#include <sys/unistd.h>
#include <machine/syscall.h>
static char *curr_brk = NULL;
#define __NR___brk __NR_brk /* Linux brk ain't no brk(2) */
static _syscall1(void *,__brk,void *,end_data_segment)
int brk(void *end_data_segment)
{
char *new_brk;
new_brk = __brk(end_data_segment);
if (new_brk != end_data_segment) return -1;
curr_brk = new_brk;
return 0;
}
void *sbrk(size_t increment) /* SHOULD be ptrdiff_t */
{
char *old_brk,*new_brk;
if (!curr_brk) curr_brk = __brk(NULL);
new_brk = __brk(curr_brk+increment);
if (new_brk != curr_brk+increment) return (void *) -1;
old_brk = curr_brk;
curr_brk = new_brk;
return old_brk;
}