What does `end` mean in a Fortran read statement?

Question

What does the end= in this code snippet mean?

read(portNum, 100, end =900) readline  

P.S. I already tried Google to find this, without luck.

Answer 1

@user3600286:

Quoted directly from this pdf:

END=900 instructs the program to go to heading 900 in the event all records have been read

The 'readline' at the end appears to be a string variable (would have been defined earlier in the program) that temporarily holds each line read in from the file.