Home
Reference Guides
Reference guides are available for functions and commands supported by OML, Tcl, and Python.
Reference Guide for OpenMatrix Language Functions
The Reference Guide contains documentation for all functions supported in the OpenMatrix language.
File I/O Commands
stderr
Returns the file ID corresponding to the error stream.

Welcome
What's New
Discover new features and enhancements.
Get Started
Discover Compose, including its language support and system requirements.
Tutorials
The Compose tutorials and associated example model files help introduce you to the basic functionality of the software.
User Guide
Learn about the features and functionality available in Compose.
Reference Guides
Reference guides are available for functions and commands supported by OML, Tcl, and Python.
- Scripting Guide for OpenMatrix Language
  OpenMatrix is a mathematical scripting language.
- Reference Guide for OpenMatrix Language Functions
  The Reference Guide contains documentation for all functions supported in the OpenMatrix language.
  - ABF Commands
  - Altair Integration Commands
  - Audio Commands
  - CAE Commands
  - CAE Reader Commands
  - CAE Reader 3D Commands
  - CAE Writer Commands
  - Calculus Commands
  - Computer Vision Commands
  - Communication Commands
  - Control System Commands
  - Core Minimal Interpreter Commands
  - Data Structure Commands
  - Differential Equations Commands
  - Elementary Math Commands
  - File I/O Commands
    - copyfile
      Returns R after copying file(s) or directories from src to dst.
    - csvread
      Reads the values of a 2D matrix, R, from the file, f, where the values are comma-separated.
    - csvwrite
      Writes the values of a 2D matrix, m, to the file, f, where the values are comma-separated.
    - dlmread
      Reads the values of a 2D matrix, R, from the file, f.
    - dlmwrite
      Writes the values of a 2D matrix, m, to the file, f.
    - fclose
      Closes a file opened by fopen(). Requires the fileID returned by fopen as an argument.
    - feof
      Returns 1 if an end-of-file symbol is encountered.
    - ferror
      Display the error status of fileID.
    - fflush
      Flush buffered output to fileID to be written the file.
    - fgetl
      Reads the characters in a file until reaching request_length of characters read. Reads until a new line or end of file if request_length is not provided.
    - fgets
      Reads the characters in a file until hitting len of characters read, a new line or end of file if len is not provided.
    - fileparts
      Returns the directory, name, and extension components of the file filepath.
    - fopen
      Opens a file, filename, for read/write operations.
    - fprintf
      This function writes output to a file using the printf format_string capabilities. The first argument is a fileID returned from an earlier call to fopen.
    - fread
      Reads the binary data of the precision type from the file fileID.
    - frewind
      Moves the file pointer to the beginning of the file fileID. Returns 0 on success.
    - fscanf
      Returns result R after reading a formatted data from file handle, f, specified by template t.
    - fseek
      Sets the file pointer to a position in fileID. Returns 0 if successful; returns -1 if unsuccessful.
    - ftell
      Returns the current position of the file pointer.
    - fullfile
      Returns a filename from dir1...dirN and filename fname.
    - fwrite
      Writes binary data to the file ID.
    - getprojectdata
      Returns all entities saved in a Project (.aprj) file: breakpoints, files, plots, source code and variables.
    - importdata
      Returns result R after reading a file, f. Different reading mechanisms are used, based on the type of file, f.
    - isdir
      Returns true if dir is a directory.
    - isfile
      Returns true if the input argument is a file.
    - ismac
      Returns true if the application is running on OSX.
    - ispc
      Returns true if the application is running on a Windows operating system.
    - isunix
      Returns true if the application is running on a Unix system.
    - load
      Reads the content of a MAT file.
    - movefile
      Returns R after moving file(s) or directories from src to dst.
    - omlfilename
      Returns the filename of the currently running script.
    - omllinenumber
      Returns the line number of the currently running script.
    - pathsep
      Displays or sets the character used to separate directories in the path.
    - printf
      Displays the string str to the Command window or Console prompt.
    - pwd
      Returns the current working directory.
    - rename
      Updates a file name from oldname to newname. Returns 0 if successful and non-zero otherwise. An optional output argument, errormessage, can be used to retrieve any additional system error messages on failure.
    - save
      Save variables in a the .MAT format file
    - SEEK_CUR
      Used in the fseek function to change the file position relative to the current file position.
    - SEEK_END
      Used in the fseek function to change the file position relative to the end of the file.
    - SEEK_SET
      Used in the fseek function to change the file position relative to the beginning of the file.
    - stderr
      Returns the file ID corresponding to the error stream.
    - stdin
      Returns the numeric file ID corresponding to the standard input stream of the application console mode.
    - stdout
      Returns the numeric file ID corresponding to the standard output stream of the application console mode.
    - textread
      Returns result R after reading a formatted data from a file, f, specified by an optional template, t.
    - textscan
      Returns result R after reading a formatted data from a file stream \, f, or string, s.
    - unzip
      Extracts file(s) from the archive, archive, and is defined in the omlziptoolbox.
    - xlsclose
      Closes an Excel file opened through the command, xlsopen, and whose details are in data with functions defined in omlxlstoolbox. xlsclose is available only on Windows systems where Microsoft Excel is installed.
    - xlsfinfo
      Provides information relevant to spreadsheets in file. This command is only available on Windows at this time.
    - xlsopen
      Opens an Excel compatible file, file, and stores the information in R using functions defined in omlxlstoolbox. xlsopen is available only on Windows systems where Microsoft Excel is installed.
    - xlsread
      Reads data, which is an Excel-compatible file or a structure returned from xlsopen. This command is only available on Windows at this time.
    - xlswrite
      Writes data to file, which is either an Excel-compatible file or a structure returned from xlsopen. This command is only available on Windows at this time.
    - zip
      Archives the file(s), files, and is defined in the omlziptoolbox.
  - Geometry Commands
  - GUI Commands
  - HDF5 Reader Commands
  - HDF5 Writer Commands
  - hstpyfit Commands
  - Image Commands
  - JSON Commands
  - Library Manager Commands
  - Linear Algebra Commands
  - Logical Commands
  - Machine Learning Commands
  - Optimization Commands
  - Plotting Commands
  - PSIM Commands
  - Polynomial Math Commands
  - Signal Processing Commands
  - Special Functions Commands
  - Statistical Analysis Commands
  - String Operations Commands
  - System Commands
  - Table Commands
  - Tcl Bridge OML Commands
  - Tcl Bridge Tcl Commands
  - Time Commands
  - Trigonometry Commands
  - OML to Python Bridge Commands
  - Python to OML Bridge Commands
- Python in Compose Reference Guide
Appendix
Get help for the optional libraries that are available in the Extension Manager.
Frequently Asked Questions
You've got questions? We've got answers!

stderr

Returns the file ID corresponding to the error stream.

Syntax

R = stderr()

Example

R = stderr()

R = 2