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(g77-295.info)Ugly Complex Part Extraction

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Ugly Complex Part Extraction
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   The `-fugly-complex' option enables use of the `REAL()' and `AIMAG()'
intrinsics with arguments that are `COMPLEX' types other than
`COMPLEX(KIND=1)'.

   With `-ff90' in effect, these intrinsics return the unconverted real
and imaginary parts (respectively) of their argument.

   With `-fno-f90' in effect, these intrinsics convert the real and
imaginary parts to `REAL(KIND=1)', and return the result of that
conversion.

   Due to this ambiguity, the GNU Fortran language defines these
constructs as invalid, except in the specific case where they are
entirely and solely passed as an argument to an invocation of the
`REAL()' intrinsic.  For example,

     REAL(REAL(Z))

is permitted even when `Z' is `COMPLEX(KIND=2)' and `-fno-ugly-complex'
is in effect, because the meaning is clear.

   `g77' enforces this restriction, unless `-fugly-complex' is
specified, in which case the appropriate interpretation is chosen and
no diagnostic is issued.

   Note: CMPAMBIG, for information on how to cope with existing code
with unclear expectations of `REAL()' and `AIMAG()' with
`COMPLEX(KIND=2)' arguments.

   Note: RealPart Intrinsic, for information on the `REALPART()'
intrinsic, used to extract the real part of a complex expression
without conversion.  Note: ImagPart Intrinsic, for information on the
`IMAGPART()' intrinsic, used to extract the imaginary part of a complex
expression without conversion.