6.3.1 Intrinsic Function References

Fortran library function names are called intrinsic function names. Normally, a name in the table of intrinsic function names (Section C.2) refers to the Fortran library function with that name. However, the name can refer to a user-defined function when the name appears in an EXTERNAL statement.

Note

If you call an intrinsic function by using the wrong number of arguments or an incorrect argument type, the compiler assumes you are referring to an external function. For example, intrinsic function SIN requires one argument; if you specify two arguments, such as in SIN (10,4), the compiler assumes SIN is external and not intrinsic.

Except when used in an EXTERNAL statement, intrinsic function names are local to the program unit that refers to them, so they can be used for other purposes in other program units. The data type of an intrinsic function does not change if you use an IMPLICIT statement to change the implied data type rules.

Intrinsic and user-defined functions cannot have the same name if they appear in the same program unit.

For More Information:

For details on the EXTERNAL statement, see Section 4.8.