2.5-18.1

misc/sbrk.c

@@ -0,0 +1,56 @@
+/* Copyright (C) 1991,1995,1996,1997,2000,2002 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <unistd.h>
+#include <errno.h>
+
+/* Defined in brk.c.  */
+extern void *__curbrk;
+extern int __brk (void *addr);
+
+/* Defined in init-first.c.  */
+extern int __libc_multiple_libcs attribute_hidden;
+
+/* Extend the process's data space by INCREMENT.
+   If INCREMENT is negative, shrink data space by - INCREMENT.
+   Return start of new space allocated, or -1 for errors.  */
+void *
+__sbrk (intptr_t increment)
+{
+  void *oldbrk;
+
+  /* If this is not part of the dynamic library or the library is used
+     via dynamic loading in a statically linked program update
+     __curbrk from the kernel's brk value.  That way two separate
+     instances of __brk and __sbrk can share the heap, returning
+     interleaved pieces of it.  */
+  if (__curbrk == NULL || __libc_multiple_libcs)
+    if (__brk (0) < 0)		/* Initialize the break.  */
+      return (void *) -1;
+
+  if (increment == 0)
+    return __curbrk;
+
+  oldbrk = __curbrk;
+  if (__brk (oldbrk + increment) < 0)
+    return (void *) -1;
+
+  return oldbrk;
+}
+libc_hidden_def (__sbrk)
+weak_alias (__sbrk, sbrk)