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Logical Values

The macros F77_FALSE and F77_TRUE expand to the numerical values that FORTRAN treats as false and true (e.g. 0 and 1). They should be used when setting logical values to be returned to the calling FORTRAN routine. There are also macros F77_ISFALSE and F77_ISTRUE that should be used when testing a function argument for truth or falsehood.



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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