The int64 is a reserved word defining that the passed or returned value of functions exported from the dll has the long long type (64-bit representation of an integer).
Due to architectural specifics of PowerLanguage, before passing the long long type value in a dll (or when the values were returned from a dll) it is converted from the "double" type (or into "double" type). Note that precision of the double type values is 15 decimals. (Values range of the long long type is from -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807 - 19 decimal points). It means that without loss of accuracy the values with the range from -999,999,999,999,999 to 999,999,999,999,999 will be passed.
Defines the dll function, which receives long long parameter:
Defines the dll function, which returns long long value: