newlib/libc/reent/sbrkr.c

   1 /* Reentrant version of sbrk system call. */
   2
   3 #include <reent.h>
   4 #include <unistd.h>
   5 #include <_syslist.h>
   6
   7 /* Some targets provides their own versions of these functions.  Those
   8    targets should define REENTRANT_SYSCALLS_PROVIDED in TARGET_CFLAGS.  */
   9
  10 #ifdef _REENT_ONLY
  11 #ifndef REENTRANT_SYSCALLS_PROVIDED
  12 #define REENTRANT_SYSCALLS_PROVIDED
  13 #endif
  14 #endif
  15
  16 #if defined (REENTRANT_SYSCALLS_PROVIDED)
  17
  18 int _dummy_sbrk_syscalls = 1;
  19
  20 #else
  21
  22 /* We use the errno variable used by the system dependent layer.  */
  23 #undef errno
  24 extern int errno;
  25
  26 /*
  27 FUNCTION
  28         <<_sbrk_r>>---Reentrant version of sbrk
  29
  30 INDEX
  31         _sbrk_r
  32
  33 SYNOPSIS
  34         #include <reent.h>
  35         void *_sbrk_r(struct _reent *<[ptr]>, ptrdiff_t <[incr]>);
  36
  37 DESCRIPTION
  38         This is a reentrant version of <<sbrk>>.  It
  39         takes a pointer to the global data block, which holds
  40         <<errno>>.
  41 */
  42
  43 void *
  44 _sbrk_r (struct _reent *ptr,
  45      ptrdiff_t incr)
  46 {
  47   char *ret;
  48   void *_sbrk(ptrdiff_t);
  49
  50   errno = 0;
  51   if ((ret = (char *)(_sbrk (incr))) == (void *) -1 && errno != 0)
  52     _REENT_ERRNO(ptr) = errno;
  53   return ret;
  54 }
  55
  56 #endif /* ! defined (REENTRANT_SYSCALLS_PROVIDED) */