f_format_variants.f90 File Reference

Demonstrates NetCDF classic format variants (CDF-1, CDF-2, CDF-5) in Fortran. More...

Functions/Subroutines
program	f_format_variants
subroutine	create_format_file (filename, format_flag, format_name)

Detailed Description

Demonstrates NetCDF classic format variants (CDF-1, CDF-2, CDF-5) in Fortran.

This is the Fortran equivalent of format_variants.c, demonstrating the three classic NetCDF format variants using the Fortran 90 NetCDF API. The program creates identical data structures in each format and compares their characteristics.

Learning Objectives:

• Understand format flags in Fortran (NF90_CLASSIC_MODEL, NF90_64BIT_OFFSET, NF90_64BIT_DATA)
• Learn format detection with nf90_inq_format()
• Compare file sizes and format characteristics
• Make informed format choices in Fortran applications

Fortran Format Constants:

• NF90_CLASSIC_MODEL - CDF-1 format (2GB limits)
• NF90_64BIT_OFFSET - CDF-2 format (4GB variable limit)
• NF90_64BIT_DATA - CDF-5 format (unlimited sizes)

Prerequisites:

• f_simple_2D.f90 - Basic file operations
• format_variants.c - C equivalent for comparison

Related Examples:

• format_variants.c - C equivalent
• f_size_limits.f90 - Demonstrates actual size limits
• f_simple_nc4.f90 - NetCDF-4 format alternative

Compilation:

gfortran -o f_format_variants f_format_variants.f90 -lnetcdff -lnetcdf

Usage:

./f_format_variants
ls -lh f_format_*.nc

Author

Edward Hartnett, Intelligent Data Design, Inc.

Date

2026

Function/Subroutine Documentation

create_format_file()

subroutine f_format_variants::create_format_file	(	character(len=*), intent(in)	filename,
		integer, intent(in)	format_flag,
		character(len=*), intent(in)	format_name
	)

f_format_variants()

program f_format_variants