Appendix B. XL Fortran internal limits

Language Feature Limit
Maximum number of iterations performed by DO loops with loop control with index variable of type INTEGER(n) for n = 1, 2 or 4 (2**31)-1
Maximum number of iterations performed by DO loops with loop control with index variable of type INTEGER(8) (2**63)-1
Maximum character format field width (2**31)-1
Maximum length of a format specification (2**31)-1
Maximum length of Hollerith and character constant edit descriptors (2**31)-1
Maximum length of a fixed source form statement 34 000
Maximum length of a free source form statement 34 000
Maximum number of continuation lines n/a  1 
Maximum number of nested INCLUDE lines 64
Maximum number of nested interface blocks 1 024
Maximum number of statement numbers in a computed GOTO 999
Maximum number of times a format code can be repeated (2**31)-1
Allowable record numbers and record lengths for input/output files in 32-bit mode The record number can be up to (2**63)-1. The maximum record length is (2**31)-1 bytes.
Allowable record numbers and record lengths for input/output files in 64-bit mode The record number can be up to (2**63)-1, and the record length can be up to (2**63)-1 bytes.

However, for unformatted sequential files, you must use the uwidth=64 run-time option for the record length to be greater than (2**31)-1 and up to (2**63)-1. If you use the default uwidth=32 run-time option, the maximum length of a record in an unformatted sequential file is (2**31)-1 bytes.

Allowable bound range of an array dimension The bound of an array dimension can be positive, negative, or zero within the range -(2**31) to 2**31-1 in 32-bit mode, or -(2**63) to 2**63-1 in 64-bit mode.
Allowable external unit numbers 0 to (2**31)-1  2 
Maximum numeric format field width 2 000
Maximum number of concurrent open files 1 024  3