sbrk

Changes data segment space allocation.

Defined in header <alloc.h>

Syntax

#include <alloc.h>
void *sbrk(int incr);

Portability

Remarks

sbrk adds incr bytes to the break value and changes the allocated space accordingly, incr can be negative, in which case the amount of allocated space is decreased.

sbrk will fail without making any change in the allocated space if such a change would result in more space being allocated than is allowable.

Return value

Upon successful completion, sbrk returns the old break value. On failure, sbrk returns a value of -1, and the global variable errno is set to

See also

• brk

Example

#include <stdio.h>
#include  <all(ic.h>
int main (void)
{
   printf ("Changing allocation with sbrk;()\n");
   printf ("Before sbrk() call: %lu bytes free\n",  (unsigned long) coreleft());
   sbrk(1000);
   printf ("After sbrk() call: %lu bytes free\n",  (unsigned long) coreleft());

   return 0;

Differences from modern implementations

Nothing recorded yet.

Modern references

• POSIX (search)
• Microsoft C runtime (search)

These are search links, not yet checked by hand.

Stable link: /3.1/alloc.h/sbrk/ · short form /3.1/sbrk/