COBOL and Fortran do not share files, except the Language Environment message file (the ddname specified in the Language Environment MSGFILE runtime option). You must manage all other files to ensure that no conflicts arise. Performing I/O operations on the same ddname might cause abnormal termination. If directed to the Language Environment message file, output from both COBOL and Fortran programs will be interspersed in the file.

Under COBOL, runtime messages and other related output are directed to the Language Environment message file. For COBOL programs, output from the DISPLAY UPON SYSOUT statement is also directed to the Language Environment message file if the ddname name in the MGSFILE runtime option matches that in the OUTDD compiler option. (The IBM-supplied default value for OUTDD is SYSOUT.)

Fortran runtime messages, output written to the print unit, and other output (such as output from the SDUMP callable service) are directed to the file specified by the MSGFILE runtime option. To direct this output to the file with the ddname FTnnF001, (where nn is the two-digit error message unit number), specify the runtime option MSGFILE(FTnnF001). If the print unit is different than the error message unit (if the PRTUNIT and the ERRUNIT runtime options have different values), output from a PRINT statement won't be directed to the Language Environment message file.