FORTRAN Reference Manual

Compiler Limits
FORTRAN Reference Manual—528615-001
E-3
I/O unit numbers must be in the range 1 through 999. You can declare up to 128
different unit numbers in a compilation.
Data files can have record lengths up to 32,767 bytes, but for most file types the
limit is 4,096 bytes. Consult the ENSCRIBE Programmer’s Guide for details.
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Records in source files and listing files can be up to 132 characters long.
Source files referenced by a SOURCE compiler directive can include further
SOURCE compiler directives, up to a maximum nesting depth of six levels.
The compiler has other limits such as the symbol table size, the amount of data it
can store from DATA and FORMAT statements, and the number of external
procedures that you can define and reference in an entire compilation. These limits
cannot be expressed in a simple way because the internal table entries involved
are variable in length. For example, the size of a symbol table entry depends on
several factors including the length of the symbolic name and the number of
dimensions.
If the compiler issues an error message saying you have exceeded a compiler
table size limit, divide your source file into two or more smaller ones with fewer
program units in each, and then use separate compiler runs to compile the whole
program.