Chapter 4. Element functions

Elements of groups, rings and fields are stored in the element_t data type. Variables of this type must be initialized before use, and should be cleared after they are no longer needed.

The element_ functions must be used with caution. Just as division by zero does not make sense for integers, some operations may not make sense for particular elements. For example, in a ring, one cannot in general invert elements.

Another caveat is that many of these functions assume their arguments come from the same ring, group or field. No implicit type casting is performed.

For debug builds, turn on run-time checks by defining PBC_DEBUG before including pbc.h:

#define PBC_DEBUG
#include <pbc.h>

Also, when PBC_DEBUG is defined, the following macros are active. Normally they are replaced with empty statements.

PBC_ASSERT(expr, msg)

Macro: if expr evaluates to 0, print msg and exit.


Macro: if elements a and b are from different fields then exit.


Macro: if elements a, b and c are from different fields then exit.