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F77_ISFALSE
- Is this the FORTRAN logical value false?
- Description:
- Does the argument of the macro evaluate to a value that FORTRAN
would treat as a LOGICAL false?
- Invocation:
- if( F77_ISFALSE(var) ) ...
- Arguments:
-
-
var
-
The name of the value to be tested.
- Examples:
-
- F77_ISFALSE(var)
- will expand as follows:
Solaris: |
( ! ( var ) ) |
OSF/1: |
( ! ( (var)&1 ) ) |
VAX/VMS: |
( ! ( (var)&1 ) ) |
- Notes:
- The VAX FORTRAN and DEC FORTRAN for RISC compilers only use the
lowest bit for the logical flag.
Hence 0 = false, 1 = true, 2 = false, 3 = true, etc.
- The Sun FORTRAN compiler uses zero = false, non zero = true.
- The FORTRAN for RISC compiler (from MIPS) on the DECstation
uses zero = false, non zero = true. This means that the correct
value of this C macro depends on which FORTRAN compiler is
being used.
Next: F77_ISTRUE - Is this the FORTRAN logical value true?
Up: Full Description of F77 Macros
Previous: F77_INTEGER_TYPE - Define the type INTEGER
CNF and F77 Mixed Language Programming -- FORTRAN and C
Starlink User Note 209
P.M. Allan
A.J. Chipperfield
R.F. Warren-Smith
19 January 2000
E-mail:ussc@star.rl.ac.uk