FORTRAN Reference Manual

FORTRAN Reference Manual—528615-001
E-1
E Compiler Limits
This appendix summarizes the limits of the FORTRAN compiler.
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Symbolic names can be up to 31 characters long. FORTRAN discards characters
beyond the 31st. Therefore, the following two identifiers are the same:
abcdefghijklmnopqrstuvwxyz123456
abcdefghijklmnopqrstuvwxyz123457
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Executable programs
An executable program must have exactly one main program.
The object code for an executable program can have up to 16 memory segments
(65,536 words per segment) if you use a user library object file in addition to the
program file. If you do not use a user library, your program file can have up to 32
segments.
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Statements
A source statement can have one initial line and up to 19 continuation lines, or a
total of 20 lines per statement.
A source statement can be composed of up to 1,320 characters. (A statement
using columns 7 through 72 of each of 20 lines uses 1,320 characters.) A source
statement can contain more than 1,320 characters if you use columns beyond
column 72 to contain program text.
A computed GO TO statement can specify to 255 statement labels in its list.
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Subprograms
The object code for a single program unit can be up to 32,768 words, including all
executable instructions and read-only data such as constants and translated
FORMAT statements, but not including local variables and arrays.
A single program unit can contain up to 501 ASSIGN statements.
External subprograms can have up to 63 dummy arguments.
A subprogram that includes ENTRY statements can have up to 63 unique dummy
arguments; a dummy argument for more than one entry point in the same
subprogram is counted only once.
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Statement functions
A statement function can have any number of dummy arguments as long as the
dummy arguments do not require more than 31 words of storage. The space
required for each type of parameter is: