astIsDynamicastIsDynamic - Returns a flag indicating if memory was allocated dynamically

Description:
This function takes a pointer to a region of memory and tests if the memory has previously been dynamically allocated using other functions from this module. It does this by checking for the presence of a "magic" number in the header which precedes the allocated memory. If the magic number is not present (or the pointer is invalid for any other reason), zero is returned. Otherwise 1 is returned.
Synopsis:
int astIsDynamic_( const void $*$ptr )
Parameters:
ptr
Pointer to test.
Returned Value:
astIsDynamic()
Non-zero if the memory was allocated dynamically. Zero is returned if the supplied pointer is NULL.
Notes:
  • A value of zero is returned if this function is invoked with the global error status set, or if it fails for any reason.