Code before warnings are enabled at line 6, column 1.  See page 431 of PBP.  (Severity: 4)
Two-argument "open" used at line 63, column 5.  See page 207 of PBP.  (Severity: 5)
Return value of "open" ignored at line 63, column 5.  Check the return value of "open" for success.  (Severity: 3)
Return value of "close" ignored at line 68, column 5.  Check the return value of "close" for success.  (Severity: 2)
Two-argument "open" used at line 78, column 5.  See page 207 of PBP.  (Severity: 5)
Return value of "open" ignored at line 78, column 5.  Check the return value of "open" for success.  (Severity: 3)
Return value of "close" ignored at line 80, column 5.  Check the return value of "close" for success.  (Severity: 2)
Expression form of "eval" at line 82, column 21.  See page 161 of PBP.  (Severity: 5)
Two-argument "open" used at line 88, column 5.  See page 207 of PBP.  (Severity: 5)
Return value of "open" ignored at line 88, column 5.  Check the return value of "open" for success.  (Severity: 3)