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Fortran Library Reference

getfd: Get File Descriptor for External Unit Number

The function is called by:

INTEGER*4 getfd

fildes = getfd( unitn )

unitn

INTEGER*4

Input 

External unit number 

Return value 

INTEGER*4 -or- INTEGER*8

Output 

File descriptor if file is connected; -1 if file is not connected An INTEGER*8 result is returned when compiling for 64-bit environments

Example: getfd(): 

    INTEGER*4 fildes, getfd, unitn/1/
    open( unitn, file='tgetfd.data' )
    fildes = getfd( unitn )
    if ( fildes .eq. -1 ) stop 'getfd: file not connected'
    write(*,*) 'file descriptor = ', fildes
    end

See also open(2).