How to use

sysconf

method

in

libcore.io.Os

/**
 * Returns the number of processor cores available to the VM, at least 1.
 * Traditionally this returned the number currently online,
 * but many mobile devices are able to take unused cores offline to
 * save power, so releases newer than Android 4.2 (Jelly Bean) return the maximum number of
 * cores that could be made available if there were no power or heat
 * constraints.
 */
public int availableProcessors() {
  return (int) Libcore.os.sysconf(_SC_NPROCESSORS_CONF);
}

public long sysconf(int name) { return os.sysconf(name); }
public void tcdrain(FileDescriptor fd) throws ErrnoException { os.tcdrain(fd); }

/**
 * Returns true if there is a high probability that every page of this buffer is currently
 * loaded in RAM, meaning that accesses will not cause a page fault. It is impossible to give
 * a strong guarantee since this is only a snapshot of a dynamic situation.
 */
public final boolean isLoaded() {
 checkIsMapped();
 long address = block.toLong();
 long size = block.getSize();
 if (size == 0) {
  return true;
 }
 try {
  int pageSize = (int) Libcore.os.sysconf(_SC_PAGE_SIZE);
  int pageOffset = (int) (address % pageSize);
  address -= pageOffset;
  size += pageOffset;
  int pageCount = (int) ((size + pageSize - 1) / pageSize);
  byte[] vector = new byte[pageCount];
  Libcore.os.mincore(address, size, vector);
  for (int i = 0; i < vector.length; ++i) {
   if ((vector[i] & 1) != 1) {
    return false;
   }
  }
  return true;
 } catch (ErrnoException errnoException) {
  return false;
 }
}

long alignment = position - position % Libcore.os.sysconf(_SC_PAGE_SIZE);
int offset = (int) (position - alignment);
MemoryBlock block = MemoryBlock.mmap(fd, alignment, size + offset, mapMode);

/**
 * Returns the number of processor cores available to the VM, at least 1.
 * Traditionally this returned the number currently online,
 * but many mobile devices are able to take unused cores offline to
 * save power, so releases newer than Android 4.2 (Jelly Bean) return the maximum number of
 * cores that could be made available if there were no power or heat
 * constraints.
 */
public int availableProcessors() {
  return (int) Libcore.os.sysconf(_SC_NPROCESSORS_CONF);
}

/**
 * Returns the number of processor cores available to the VM, at least 1.
 * Traditionally this returned the number currently online,
 * but many mobile devices are able to take unused cores offline to
 * save power, so releases newer than Android 4.2 (Jelly Bean) return the maximum number of
 * cores that could be made available if there were no power or heat
 * constraints.
 */
public int availableProcessors() {
  return (int) Libcore.os.sysconf(_SC_NPROCESSORS_CONF);
}

/**
 * Returns the number of processor cores available to the VM, at least 1.
 * Traditionally this returned the number currently online,
 * but many mobile devices are able to take unused cores offline to
 * save power, so releases newer than Android 4.2 (Jelly Bean) return the maximum number of
 * cores that could be made available if there were no power or heat
 * constraints.
 */
public int availableProcessors() {
  return (int) Libcore.os.sysconf(_SC_NPROCESSORS_CONF);
}

/**
 * Returns the number of processor cores available to the VM, at least 1.
 * Traditionally this returned the number currently online,
 * but many mobile devices are able to take unused cores offline to
 * save power, so releases newer than Android 4.2 (Jelly Bean) return the maximum number of
 * cores that could be made available if there were no power or heat
 * constraints.
 */
public int availableProcessors() {
  return (int) Libcore.os.sysconf(_SC_NPROCESSORS_CONF);
}

/**
 * Returns the number of processor cores available to the VM, at least 1.
 * Traditionally this returned the number currently online,
 * but many mobile devices are able to take unused cores offline to
 * save power, so releases newer than Android 4.2 (Jelly Bean) return the maximum number of
 * cores that could be made available if there were no power or heat
 * constraints.
 */
public int availableProcessors() {
  return (int) Libcore.os.sysconf(_SC_NPROCESSORS_CONF);
}

/**
 * Returns the number of processor cores available to the VM, at least 1.
 * Traditionally this returned the number currently online,
 * but many mobile devices are able to take unused cores offline to
 * save power, so releases newer than Android 4.2 (Jelly Bean) return the maximum number of
 * cores that could be made available if there were no power or heat
 * constraints.
 */
public int availableProcessors() {
  return (int) Libcore.os.sysconf(_SC_NPROCESSORS_CONF);
}

public long sysconf(int name) { return os.sysconf(name); }
public void tcdrain(FileDescriptor fd) throws ErrnoException { os.tcdrain(fd); }

public long sysconf(int name) { return os.sysconf(name); }
public void tcdrain(FileDescriptor fd) throws ErrnoException { os.tcdrain(fd); }

public long sysconf(int name) { return os.sysconf(name); }
public void tcdrain(FileDescriptor fd) throws ErrnoException { os.tcdrain(fd); }

public long sysconf(int name) { return os.sysconf(name); }
public void tcdrain(FileDescriptor fd) throws ErrnoException { os.tcdrain(fd); }

public long sysconf(int name) { return os.sysconf(name); }
public void tcdrain(FileDescriptor fd) throws ErrnoException { os.tcdrain(fd); }

public long sysconf(int name) { return os.sysconf(name); }
public void tcdrain(FileDescriptor fd) throws ErrnoException { os.tcdrain(fd); }

/**
 * Returns true if there is a high probability that every page of this buffer is currently
 * loaded in RAM, meaning that accesses will not cause a page fault. It is impossible to give
 * a strong guarantee since this is only a snapshot of a dynamic situation.
 */
public final boolean isLoaded() {
 checkIsMapped();
 long address = block.toLong();
 long size = block.getSize();
 if (size == 0) {
  return true;
 }
 try {
  int pageSize = (int) Libcore.os.sysconf(_SC_PAGE_SIZE);
  int pageOffset = (int) (address % pageSize);
  address -= pageOffset;
  size += pageOffset;
  int pageCount = (int) ((size + pageSize - 1) / pageSize);
  byte[] vector = new byte[pageCount];
  Libcore.os.mincore(address, size, vector);
  for (int i = 0; i < vector.length; ++i) {
   if ((vector[i] & 1) != 1) {
    return false;
   }
  }
  return true;
 } catch (ErrnoException errnoException) {
  return false;
 }
}

/**
 * Returns true if there is a high probability that every page of this buffer is currently
 * loaded in RAM, meaning that accesses will not cause a page fault. It is impossible to give
 * a strong guarantee since this is only a snapshot of a dynamic situation.
 */
public final boolean isLoaded() {
 checkIsMapped();
 long address = block.toLong();
 long size = block.getSize();
 if (size == 0) {
  return true;
 }
 try {
  int pageSize = (int) Libcore.os.sysconf(_SC_PAGE_SIZE);
  int pageOffset = (int) (address % pageSize);
  address -= pageOffset;
  size += pageOffset;
  int pageCount = (int) ((size + pageSize - 1) / pageSize);
  byte[] vector = new byte[pageCount];
  Libcore.os.mincore(address, size, vector);
  for (int i = 0; i < vector.length; ++i) {
   if ((vector[i] & 1) != 1) {
    return false;
   }
  }
  return true;
 } catch (ErrnoException errnoException) {
  return false;
 }
}

/**
 * Returns true if there is a high probability that every page of this buffer is currently
 * loaded in RAM, meaning that accesses will not cause a page fault. It is impossible to give
 * a strong guarantee since this is only a snapshot of a dynamic situation.
 */
public final boolean isLoaded() {
 checkIsMapped();
 long address = block.toLong();
 long size = block.getSize();
 if (size == 0) {
  return true;
 }
 try {
  int pageSize = (int) Libcore.os.sysconf(_SC_PAGE_SIZE);
  int pageOffset = (int) (address % pageSize);
  address -= pageOffset;
  size += pageOffset;
  int pageCount = (int) ((size + pageSize - 1) / pageSize);
  byte[] vector = new byte[pageCount];
  Libcore.os.mincore(address, size, vector);
  for (int i = 0; i < vector.length; ++i) {
   if ((vector[i] & 1) != 1) {
    return false;
   }
  }
  return true;
 } catch (ErrnoException errnoException) {
  return false;
 }
}

/**
 * Returns true if there is a high probability that every page of this buffer is currently
 * loaded in RAM, meaning that accesses will not cause a page fault. It is impossible to give
 * a strong guarantee since this is only a snapshot of a dynamic situation.
 */
public final boolean isLoaded() {
 checkIsMapped();
 long address = block.toLong();
 long size = block.getSize();
 if (size == 0) {
  return true;
 }
 try {
  int pageSize = (int) Libcore.os.sysconf(_SC_PAGE_SIZE);
  int pageOffset = (int) (address % pageSize);
  address -= pageOffset;
  size += pageOffset;
  int pageCount = (int) ((size + pageSize - 1) / pageSize);
  byte[] vector = new byte[pageCount];
  Libcore.os.mincore(address, size, vector);
  for (int i = 0; i < vector.length; ++i) {
   if ((vector[i] & 1) != 1) {
    return false;
   }
  }
  return true;
 } catch (ErrnoException errnoException) {
  return false;
 }
}