Fortran Runtime Library¶

The EWTS Fortran runtime library provides logging support for Fortran-based hydrologic models running either within ngen or as standalone applications.

Typical use¶

A Fortran module initializes its module logger and writes messages through the EWTS runtime:

use logger
use ewts_module_constants

call logger_init_module(EWTS_ID_NOAH_OWP_MODULAR)
call write_log("Initializing NOAHOWP BMI", EWTS_INFO)

Legacy wrapper compatibility¶

Many existing Fortran modules use wrapper modules such as noahowp_log_module so large call sites do not need to change all at once.

A wrapper can preserve legacy names such as LOG_LEVEL_INFO while mapping them to canonical EWTS values such as EWTS_INFO.

When running under ngen¶

Initialize the module logger before the first log message, ideally in the BMI Initialize routine. This ensures that the correct module identity and per-module configuration are applied from the start of execution.

Developer reference¶

For implementation details, initialization guidance, and backward-compatibility patterns, see:

• runtime/fortran/README.md