# A to B

This section describes language features that start with A or B.

Parent topic: A to Z Reference

- ABORT
  Portability Subroutine: Flushes and closes I/O buffers, and terminates program execution.
- ABS
  Elemental Intrinsic Function (Generic): Computes an absolute value.
- ABSTRACT INTERFACE
  Statement: Defines an abstract interface.
- ACCEPT
  Statement: Transfers input data.
- ACCESS Function
  Portability Function: Determines if a file exists and how it can be accessed.
- ACHAR
  Elemental Intrinsic Function (Generic): Returns the character in a specified position of the ASCII character set, even if the processor's default character set is different. It is the inverse of the IACHAR function. In Intel® Fortran, ACHAR is equivalent to the CHAR function.
- ACOS
  Elemental Intrinsic Function (Generic): Produces the arccosine of x.
- ACOSD
  Elemental Intrinsic Function (Generic): Produces the arccosine of x.
- ACOSH
  Elemental Intrinsic Function (Generic): Produces the hyperbolic arccosine of x.
- ADJUSTL
  Elemental Intrinsic Function (Generic): Adjusts a character string to the left, removing leading blanks and inserting trailing blanks.
- ADJUSTR
  Elemental Intrinsic Function (Generic): Adjusts a character string to the right, removing trailing blanks and inserting leading blanks.
- AIMAG
  Elemental Intrinsic Function (Generic): Returns the imaginary part of a complex number. This function can also be specified as IMAG.
- AINT
  Elemental Intrinsic Function (Generic): Truncates a value to a whole number.
- ALARM
  Portability Function: Causes a subroutine to begin execution after a specified amount of time has elapsed.
- ALIAS Directive
  General Compiler Directive: Declares alternate external names for external subprograms.
- ALIGNED Clause
  Parallel Directive Clause: Specifies that all variables in a list are aligned.
- ALL
  Transformational Intrinsic Function (Generic): Determines if all values are true in an entire array or in a specified dimension of an array.
- ALLOCATABLE
  Statement and Attribute: Specifies that an object is allocatable. The shape of an allocatable array is determined when an ALLOCATE statement is executed, dynamically allocating space for the array. A character object may have a deferred length that is determined when the object is allocated with an ALLOCATE statement. A allocatable scalar object of any type may be allocated with an ALLOCATE statement.
- ALLOCATE Clause
  Directive Clause: Specifies the memory allocator to be used for one or more private variables or common blocks of a construct. This feature is only available for ifx.
- ALLOCATE Directive
  OpenMP* Fortran Compiler Directive: Specifies memory allocators to use for object allocation and deallocation. This feature is only available for ifx.
- ALLOCATE Statement
  Statement: Dynamically creates storage for allocatable variables and pointer targets.
- ALLOCATED
  Inquiry Intrinsic Function (Generic): Indicates whether an allocatable array or allocatable scalar is currently allocated.
- ANINT
  Elemental Intrinsic Function (Generic): Calculates the nearest whole number.
- ANY
  Transformational Intrinsic Function (Generic): Determines if any value is true in an entire array or in a specified dimension of an array.
- ASIN
  Elemental Intrinsic Function (Generic): Produces the arcsine of an argument.
- ASIND
  Elemental Intrinsic Function (Generic): Produces the arcsine of x.
- ASINH
  Elemental Intrinsic Function (Generic): Produces the hyperbolic arcsine of x.
- ASSIGN - Label Assignment
  Statement: Assigns a statement label value to an integer variable. This feature has been deleted in the Fortran Standard. Intel® Fortran fully supports features deleted in the Fortran Standard.
- Assignment(=) - Defined Assignment
  Statement: An interface block that defines generic assignment. The only procedures allowed in the interface block are subroutines that can be referenced as defined assignments.
- Assignment - Intrinsic Computational
  Statement: Assigns a value to a nonpointer variable. In the case of pointers, intrinsic assignment is used to assign a value to the target associated with the pointer variable. The value assigned to the variable (or target) is determined by evaluation of the expression to the right of the equal sign.
- ASSOCIATE
  Statement: Marks the beginning of an ASSOCIATE construct. The ASSOCIATE construct creates a temporary association between a named entity and a variable or the value of an expression. The association lasts for the duration of the block.
- ASSOCIATED
  Inquiry Intrinsic Function (Generic): Returns the association status of its pointer argument or indicates whether the pointer is associated with the target.
- ASSUME
  General Compiler Directive: Provides heuristic information to the compiler optimizer.
- ASSUME_ALIGNED
  General Compiler Directive: Specifies that an entity in memory is aligned.
- ASYNCHRONOUS
  Statement and Attribute: Specifies that a variable can be used for asynchronous input and output.
- ATAN
  Elemental Intrinsic Function (Generic): Produces the arctangent of an argument.
- ATAN2
  Elemental Intrinsic Function (Generic): Produces an arctangent (inverse tangent). The result is the principal value of the argument of the nonzero complex number (x, y).
- ATAN2D
  Elemental Intrinsic Function (Generic): Produces an arctangent. The result is the principal value of the argument of the nonzero complex number (x, y).
- ATAND
  Elemental Intrinsic Function (Generic): Produces the arctangent of x.
- ATANH
  Elemental Intrinsic Function (Generic): Produces the hyperbolic arctangent of x.
- ATOMIC
  OpenMP* Fortran Compiler Directive: Ensures that a specific memory location is updated atomically. This prevents the possibility of multiple threads simultaneously reading and writing the specific memory location.
- ATOMIC_ADD
  Atomic Intrinsic Subroutine (Generic): Performs atomic addition.
- ATOMIC_AND
  Atomic Intrinsic Subroutine (Generic): Performs atomic bitwise AND.
- ATOMIC_CAS
  Atomic Intrinsic Subroutine (Generic): Performs atomic compare and swap.
- ATOMIC_DEFINE
  Atomic Intrinsic Subroutine (Generic): Defines a variable atomically.
- ATOMIC_FETCH_ADD
  Atomic Intrinsic Subroutine (Generic): Performs atomic fetch and addition.
- ATOMIC_FETCH_AND
  Atomic Intrinsic Subroutine (Generic): Performs atomic fetch and bitwise AND.
- ATOMIC_FETCH_OR
  Atomic Intrinsic Subroutine (Generic): Performs atomic fetch and bitwise OR.
- ATOMIC_FETCH_XOR
  Atomic Intrinsic Subroutine (Generic): Performs atomic fetch and bitwise exclusive OR.
- ATOMIC_OR
  Atomic Intrinsic Subroutine (Generic): Performs atomic bitwise OR.
- ATOMIC_REF
  Atomic Intrinsic Subroutine (Generic): Lets you reference a variable atomically.
- ATOMIC_XOR
  Atomic Intrinsic Subroutine (Generic): Performs atomic bitwise exclusive OR.
- ATTRIBUTES
  General Compiler Directive: Declares properties for specified variables.
- AUTOMATIC
  Statement and Attribute: Controls the storage allocation of variables in subprograms (as does STATIC). Variables declared as AUTOMATIC and allocated in memory reside in the stack storage area, rather than at a static memory location.
- BACKSPACE
  Statement: Positions a sequential file at the beginning of the preceding record, making it available for subsequent I/O processing. It takes one of the following forms:
- BADDRESS
  Inquiry Intrinsic Function (Generic): Returns the address of an argument. This function cannot be passed as an actual argument. This function can also be specified as IADDR.
- BARRIER
  OpenMP* Fortran Compiler Directive: Synchronizes all the threads in a team. It causes each thread to wait until all of the other threads in the team have reached the barrier.
- BEEPQQ
  Portability Subroutine: Sounds the speaker at the specified frequency for the specified duration in milliseconds.
- BESJ0, BESJ1, BESJN, BESY0, BESY1, BESYN
  Portability Functions: Compute the single-precision values of Bessel functions of the first and second kinds.
- BESSEL_J0
  Elemental Intrinsic Function (Generic): Computes a Bessel function of the first kind, order 0.
- BESSEL_J1
  Elemental Intrinsic Function (Generic): Computes a Bessel function of the first kind, order 1.
- BESSEL_JN
  Elemental and Transformational Intrinsic Functions (Generic): Compute Bessel functions of the first kind.
- BESSEL_Y0
  Elemental Intrinsic Function (Generic): Computes a Bessel function of the second kind, order 0.
- BESSEL_Y1
  Elemental Intrinsic Function (Generic): Computes a Bessel function of the second kind, order 1.
- BESSEL_YN
  Elemental and Transformational Intrinsic Functions (Generic): Compute Bessel functions of the second kind.
- BGE
  Elemental Intrinsic Function (Generic): Performs a bitwise greater than or equal to on its arguments.
- BGT
  Elemental Intrinsic Function (Generic): Performs a bitwise greater than on its arguments.
- BIC, BIS
  Portability Subroutines: Perform a bit-level set and clear for integers.
- BIND
  Statement and Attribute: Specifies that an object is interoperable with C and has external linkage.
- BIT
  Portability Function: Performs a bit-level test for integers.
- BIT_SIZE
  Inquiry Intrinsic Function (Generic): Returns the number of bits in an integer type.
- BLE
  Elemental Intrinsic Function (Generic): Performs a bitwise less than or equal to on its arguments.
- BLOCK
  Statement: Marks the beginning of a BLOCK construct. The BLOCK construct executes a block of statements or constructs that can contain declarations.
- BLOCK DATA
  Statement: Identifies a block-data program unit, which provides initial values for variables in named common blocks. BLOCK DATA is an obsolescent language feature in Standard Fortran.
- BLOCK_LOOP and NOBLOCK_LOOP
  General Compiler Directives: Enables or disables loop blocking for the immediately following nested DO loops. BLOCK_LOOP enables loop blocking for the nested loops. NOBLOCK_LOOP disables loop blocking for the nested loops.
- BLT
  Elemental Intrinsic Function (Generic): Performs a bitwise less than on its arguments.
- BSEARCHQQ
  Portability Function: Performs a binary search of a sorted one-dimensional array for a specified element. The array elements cannot be derived types or structures.
- BTEST
  Elemental Intrinsic Function (Generic): Tests a bit of an integer argument.
- BYTE
  Statement: Specifies the BYTE data type, which is equivalent to INTEGER(1).