Glossary N

name

Identifies an entity within a Fortran program unit (such as a variable, function result, common block, named constant, procedure, program unit, namelist group, or dummy argument).

A name can contain letters, digits, underscores ( _ ), and the dollar sign ($) special character. The first character must be a letter or a dollar sign. In earlier versions of Fortran, this term was called a symbolic name.

name association

Pertains to argument, host, or use association. See also argument association, host association, and use association.

named common block

A common block (one or more contiguous areas of storage) with a name. Common blocks are defined by a COMMON statement.

named constant

A constant that has a name. In earlier versions of Fortran, this term was called a symbolic constant.

namelist I/O statement

An implicit, formatted I/O statement that uses a namelist group specifier rather than an explicit format specifier. See also formatted I/O statement and list-directed I/O statement.

NaN

Not-a-Number. The condition that results from a floating-point operation that has no mathematical meaning; for example, zero divided by zero.

natural boundary

The virtual address of a data item that is the multiple of the size of its data type. For example, a REAL(8) (REAL*8) data item aligned on natural boundaries has an address that is a multiple of eight.

naturally aligned record

A record that is aligned on a hardware-specific natural boundary; each field is naturally aligned. Contrast with packed record.

nesting

The placing of one entity (such as a construct, subprogram, format specification, or loop) inside another entity of the same kind. For example, nesting a loop within another loop (a nested loop), or nesting a subroutine within another subroutine (a nested subroutine).

nonexecutable statement

A Fortran statement that describes program attributes, but does not cause any action to be taken when the program is executed.

nonsignaled

The state of an object used for synchronization in one of the wait functions is either signaled or nonsignaled. A nonsignaled state can prevent the wait function from returning. See also wait function.

normal termination

Normal termination of an image is initiated when the image executes a STOP statement or an END [PROGRAM] statement. The image becomes a stopped image. Its coarrays remain accessible to other active images and may be defined or referenced by them.

When the last active image initiates normal termination, all images terminate execution. See also error termination.

numeric expression

A numeric constant, variable, or function value, or combination of these, joined by numeric operators and parentheses, so that the entire expression can be evaluated to produce a single numeric value. For example, -L or X+(Y-4.5*Z).

numeric operator

A symbol designating an arithmetic operation. In Standard Fortran, the symbols +, -, *, /, and ** are used to designate addition, subtraction, multiplication, division, and exponentiation, respectively.

numeric storage unit

The unit of storage for holding a non-pointer scalar value of type default real, default integer, or default logical. One numeric storage unit corresponds to 4 bytes of memory.

numeric type

Integer, real, or complex type.