A related collection of methods allows you to extend this collection of flags and parameters for your own applications, without risk of conflict between them.
static fmtflags ios::bitalloc () Method
Reserve a bit (the single bit on in the result) to use as a flag. Using bitalloc guards against conflict between two packages that use ios objects for different purposes.
This method is available for upward compatibility, but is not in the ANSI working paper. The number of bits available is limited; a return value of 0 means no bit is available.
static int ios::xalloc () Method
Reserve space for a long integer or pointer parameter. The result is a unique nonnegative integer. You can use it as an index to ios::iword or ios::pword. Use xalloc to arrange for arbitrary special-purpose data in your ios objects, with-out risk of conflict between packages designed for different purposes.
long& ios::iword (int index) Method
Return a reference to arbitrary data, of long integer type, stored in an ios instance. index, conv 8b1 entionally returned from ios::xalloc, identifies what particular data you need.
long ios::iword (int index) const Method
Return the actual value of a long integer stored in an ios.
void*& ios::pword (int index) Method
Return a reference to an arbitrary pointer, stored in an ios instance. index, originally returned from ios::xalloc, identifies what particular pointer you need.
void* ios::pword (int index)const Method
Return the actual value of a pointer stored in an ios.