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#ifndef MEMMAP_H_
#define MEMMAP_H_

#include "config.h"

#ifdef _WIN32
// Windows has mmap bits defined in it's port.h header
#else
// Everything we assume is sufficiently POSIX-compatible. Also we
// assume ~everyone has MAP_ANONYMOUS or similar (POSIX, strangely,
// doesn't!)
#include <sys/mman.h>
#include <sys/types.h>

// Someone still cares about those near-obsolete OSes that fail to
// supply MAP_ANONYMOUS.
# ifndef MAP_ANONYMOUS
#  define MAP_ANONYMOUS MAP_ANON
# endif

#endif

namespace tcmalloc {

struct MMapResult {
  void* addr;
  bool success;
};

// MapAnonymous does mmap of r+w anonymous memory, simply saving us
// some hassle of spreading (not 100% portable) flags.
static inline MMapResult MapAnonymous(size_t length) {
  MMapResult result;
  result.addr = mmap(nullptr, length, PROT_READ|PROT_WRITE, MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
  result.success = (result.addr != MAP_FAILED);
  return result;
}

}  // namespace tcmalloc

#endif  // MEMMAP_H_
