Glossary L

label

An integer, from 1 to 5 digits long, that precedes a statement and identifies it. For example, labels can be used to refer to a FORMAT statement or branch target statement.

language extension

An Intel® Fortran language element or interpretation that is not part of the Fortran 2003 standard.

lexical token

A sequence of one or more characters that have an indivisible interpretation. A lexical token is the smallest meaningful unit (a basic language element) of a Fortran statement; for example, constants, and statement keywords.

library routines

Files that contain functions, subroutines, and data that can be used by Fortran programs.

For example: one library contains routines that handle the various differences between Fortran and C in argument passing and data types; another contains run-time functions and subroutines for Windows* graphics and QuickWin* applications.

Some library routines are intrinsic (automatically available) to Fortran; others may require a specific USE statement to access the module defining the routines. See also intrinsic procedure.

line

A source form record consisting of 0 or more characters. A standard Fortran line is limited to a maximum of 132 characters.

linker

A system program that creates an executable program from one or more object files produced by a language compiler or assembler. The linker resolves external references, acquires referenced library routines, and performs other processing required to create Linux* and Windows* executable files.

list-directed I/O statement

An implicit, formatted I/O statement that uses an asterisk (*) specifier rather than an explicit format specification. See also formatted I/O statement and namelist I/O statement.

listing

A printed copy of a program.

literal constant

A constant without a name; its value is directly specified in a program. See also named constant.

little endian

A method of data storage in which the least significant bit of a numeric value spanning multiple bytes is in the lowest addressed byte. This is the method used on Intel® systems. Contrast with big endian.

local entity

An entity that can be used only within the context of a subprogram (its scoping unit); for example, a statement label. A local entity has local scope. See also global entity.

local optimization

A level of optimization enabling optimizations within the source program unit and recognition of common expressions. See also optimization.

local symbol

A name defined in a program unit that is not accessible outside of that program unit.

logical constant

A constant that specifies the value .TRUE. or .FALSE..

logical expression

An integer or logical constant, variable, function value, or another constant expression, joined by a relational or logical operator. The logical expression is evaluated to a value of either true or false. For example, .NOT. 6.5 + (B .GT. D).

logical operator

A symbol that represents an operation on logical expressions. The logical operators are .AND., .OR., .NEQV., .XOR., .EQV., and .NOT..

logical unit

A channel in memory through which data transfer occurs between the program and the device or file. See also unit identifier.

longword

Four contiguous bytes (32 bits) starting on any addressable byte boundary. Bits are numbered 0 to 31. The address of the longword is the address of the byte containing bit 0. When the longword is interpreted as a signed integer, bit 31 is the sign bit. The value of signed integers is in the range -2**31 to 2**31-1. The value of unsigned integers is in the range 0 to 2**32-1.

loop

A group of statements that are executed repeatedly until an ending condition is reached.

lower bounds

See bounds.