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### 9.1 `ISO_FORTRAN_ENV`

Standard:
  Fortran 2003 and later, except when otherwise noted

The `ISO_FORTRAN_ENV` module provides the following scalar default-integer named constants:

`ATOMIC_INT_KIND`:
  Default-kind integer constant to be used as kind parameter when defining integer variables used in atomic operations. (Fortran 2008 or later.)
`ATOMIC_LOGICAL_KIND`:
  Default-kind integer constant to be used as kind parameter when defining logical variables used in atomic operations. (Fortran 2008 or later.)
`CHARACTER_KINDS`:
  Default-kind integer constant array of rank one containing the supported kind parameters of the `CHARACTER` type. (Fortran 2008 or later.)
`CHARACTER_STORAGE_SIZE`:
  Size in bits of the character storage unit.
`ERROR_UNIT`:
  Identifies the preconnected unit used for error reporting.
`FILE_STORAGE_SIZE`:
  Size in bits of the file-storage unit.
`INPUT_UNIT`:
  Identifies the preconnected unit identified by the asterisk (`*`) in `READ` statement.
`INT8`, `INT16`, `INT32`, `INT64`:
  Kind type parameters to specify an INTEGER type with a storage size of 16, 32, and 64 bits. It is negative if a target platform does not support the particular kind. (Fortran 2008 or later.)
`INTEGER_KINDS`:
  Default-kind integer constant array of rank one containing the supported kind parameters of the `INTEGER` type. (Fortran 2008 or later.)
`IOSTAT_END`:
  The value assigned to the variable passed to the `IOSTAT=` specifier of an input/output statement if an end-of-file condition occurred.
`IOSTAT_EOR`:
  The value assigned to the variable passed to the `IOSTAT=` specifier of an input/output statement if an end-of-record condition occurred.
`IOSTAT_INQUIRE_INTERNAL_UNIT`:
  Scalar default-integer constant, used by `INQUIRE` for the `IOSTAT=` specifier to denote an that a unit number identifies an internal unit. (Fortran 2008 or later.)
`NUMERIC_STORAGE_SIZE`:
  The size in bits of the numeric storage unit.
`LOGICAL_KINDS`:
  Default-kind integer constant array of rank one containing the supported kind parameters of the `LOGICAL` type. (Fortran 2008 or later.)
`OUTPUT_UNIT`:
  Identifies the preconnected unit identified by the asterisk (`*`) in `WRITE` statement.
`REAL32`, `REAL64`, `REAL128`:
  Kind type parameters to specify a REAL type with a storage size of 32, 64, and 128 bits. It is negative if a target platform does not support the particular kind. (Fortran 2008 or later.)
`REAL_KINDS`:
  Default-kind integer constant array of rank one containing the supported kind parameters of the `REAL` type. (Fortran 2008 or later.)
`STAT_LOCKED`:
  Scalar default-integer constant used as STAT= return value by `LOCK` to denote that the lock variable is locked by the executing image. (Fortran 2008 or later.)
`STAT_LOCKED_OTHER_IMAGE`:
  Scalar default-integer constant used as STAT= return value by `UNLOCK` to denote that the lock variable is locked by another image. (Fortran 2008 or later.)
`STAT_STOPPED_IMAGE`:
  Positive, scalar default-integer constant used as STAT= return value if the argument in the statement requires synchronisation with an image, which has initiated the termination of the execution. (Fortran 2008 or later.)
`STAT_FAILED_IMAGE`:
  Positive, scalar default-integer constant used as STAT= return value if the argument in the statement requires communication with an image, which has is in the failed state. (TS 18508 or later.)
`STAT_UNLOCKED`:
  Scalar default-integer constant used as STAT= return value by `UNLOCK` to denote that the lock variable is unlocked. (Fortran 2008 or later.)

The module provides the following derived type:

`LOCK_TYPE`:
  Derived type with private components to be use with the `LOCK` and `UNLOCK` statement. A variable of its type has to be always declared as coarray and may not appear in a variable-definition context. (Fortran 2008 or later.)

The module also provides the following intrinsic procedures: COMPILER_OPTIONS and COMPILER_VERSION.