# Understand Run-Time Errors

During execution, your program may encounter errors or exception conditions. These conditions can result from any of the following:

- Errors that occur during I/O operations.

- Invalid input data.

- Argument errors in calls to the mathematical library.

- Arithmetic errors.

- Other system-detected errors.

The Intel® Fortran Run-Time Library (RTL) generates appropriate messages and takes action to recover from errors whenever possible.

For a description of each Intel® Fortran run-time error message, see List of Run-Time Error Messages.

There are a few tools and aids that are useful when an application fails and you need to diagnose the error. Compiler-generated machine code listings and linker-generated map files can help you understand the effects of compiler optimizations and to see how your application is laid out in memory. They may help you interpret the information provided in a stack trace at the time of the error. See Generating Listing and Map Files.

## Forcing a Core Dump for Severe Errors

You can force a core dump for severe errors that do not usually cause a core file to be created. Before running the program, set the `FOR_DUMP_CORE_FILE` environment variable to TRUE to cause severe errors to create a core file. See the "Supported Environments Variables" topic for valid values of TRUE and FALSE.

For instance, the following C shell command sets the `FOR_DUMP_CORE_FILE` environment variable:

    setenv FOR_DUMP_CORE_FILE y

The core file is written to the current directory and can be examined using a debugger.

### Note

If you requested a core file to be created on severe errors and you do not get one when expected, the problem might be that your process limit for the allowable size of a core file is set too low (or to zero). See the man page for your shell for information on setting process limits. For example, the C shell command limit (with no arguments) will report your current settings, and `limit coredumpsize unlimited` will raise the allowable limit to your current system maximum.

Parent topic: Run-Time Errors

## See Also

Supported Environment Variables
Run-Time Default Error Processing
Run-Time Message Display and Format
Values Returned at Program Termination
Methods of Handling Errors
Use the END, EOR, and ERR Branch Specifiers
Use the IOSTAT Specifier and Fortran Exit Codes
Locate Run-Time Errors
List of Run-Time Error Messages
Generate Listing and Map Files
Signal Handling
Override the Default Run-Time Library Exception Handler
Traceback and related topics