Introduction

Dyalog includes a collection of built-in facilities that provide various services related to both the APL and the external environment. They have distinguished case-insensitive names beginning with the ⎕ symbol, and are implicitly available in a clear workspace. Collectively, these facilities are referred to as System Functions but they are variously implemented as constants, variables, functions, operators, and namespaces.

Hints and Recommendations

Dyalog can extend any of these facilities by, for example, adding extra elements, rows, or columns to a result, so code should take this possibility into account.

Name Description Form
⎕ Evaluated Input/Output Variable
⍞ Character Input/Output Variable
⎕A Alphabetic uppercase characters Variable
⎕Ⓐ or ⎕Á Underscored Alphabetic Characters Constant
⎕AI Account Information Constant
⎕AN Account Name Constant
⎕ARBIN Arbitrary Input Dyadic function
⎕ARBOUT Arbitrary Output Dyadic function
⎕AT Object Attributes Ambivalent function
⎕AV Atomic Vector Constant
⎕AVU Atomic Vector - Unicode Variable
⎕BASE Base Class Reference
⎕C Case Convert Ambivalent function
⎕CLASS Class Monadic function
⎕CLEAR Clear workspace (WS) Constant
⎕CMD Execute the Windows Command Processor or another program Monadic function
⎕CMD Start a Windows Auxiliary Processor Dyadic function
⎕CR Canonical Representation Monadic function
⎕CS Change Space Monadic function
⎕CSV Comma Separated Values Ambivalent function
⎕CT Comparison Tolerance Variable
⎕CY Copy objects into active WS Function
⎕D Digits Variable
⎕DCT Decimal Comp Tolerance Variable
⎕DF Display Format Monadic function
⎕DIV Division Method Variable
⎕DL Delay execution Function
⎕DM Diagnostic Message Constant
⎕DMX Extended Diagnostic Message Reference
⎕DQ Await and process events Monadic function
⎕DR Data Representation (Dyadic) Ambivalent function
⎕DR Data Representation (Monadic) Ambivalent function
⎕DT Datetime Dyadic function
⎕ED Edit one or more objects Ambivalent function
⎕EM Event Messages Monadic function
⎕EN Event Number Constant
⎕EX Expunge objects Monadic function
⎕EX Expunge objects Monadic function
⎕EXCEPTION Reports the most recent Microsoft .NET Exception Reference
⎕EXPORT Export objects Ambivalent function
⎕FAPPEND Append a component to File Dyadic function
⎕FAVAIL File system Availability Constant
⎕FCHK File Check and Repair Ambivalent function
⎕FCOPY Copy a File Dyadic function
⎕FCREATE Create a File Dyadic function
⎕FDROP Drop a block of components Dyadic function
⎕FERASE Erase a File Dyadic function
⎕FHIST File History Monadic function
⎕FHOLD File Hold Ambivalent function
⎕FIX Fix Ambivalent function
⎕FLIB List File Library Monadic function
⎕FMT Format array Dyadic function
⎕FMT Resolve display Monadic function
⎕FNAMES Names of tied Files Constant
⎕FNUMS Tie Numbers of tied Files Constant
⎕FPROPS File Properties Dyadic function
⎕FR Floating-Point Representation Variable
⎕FRDAC Read File Access matrix Monadic function
⎕FRDCI Read Component Information Monadic function
⎕FREAD Read a component from File Monadic function
⎕FRENAME Rename a File Dyadic function
⎕FREPLACE Replace a component on File Dyadic function
⎕FRESIZE File Resize Ambivalent function
⎕FSIZE File Size Monadic function
⎕FSTAC Set File Access matrix Dyadic function
⎕FSTIE Share-Tie a File Dyadic function
⎕FTIE Tie a File exclusively Dyadic function
⎕FUNTIE Untie Files Monadic function
⎕FX Fix definition Monadic function
⎕INSTANCES Instances Monadic function
⎕IO Index Origin Variable
⎕JSON JSON Convert Ambivalent function
⎕KL Key Labels Monadic function
⎕LC Line Count Constant
⎕LOAD Load a saved WS Function
⎕LOCK Lock a function Ambivalent function
⎕LX Latent Expression Variable
⎕MAP Map a file Abivalent function
⎕MKDIR Create a directory Ambivalent function
⎕ML Migration Level Variable
⎕MONITOR Monitor query Monadic function
⎕MONITOR Monitor set Dyadic function
⎕NA Declare a DLL function Abivalent function
⎕NAPPEND Append to File Dyadic function
⎕NC Name Classification Monadic function
⎕NCOPY Copy files and directories Dyadic function
⎕NCREATE Create a File Dyadic function
⎕NDELETE Delete a File or Directory Ambivalent function
⎕NERASE Erase a File Dyadic function
⎕NEW New Instance Monadic function
⎕NEXISTS Discover whether or not a file or directory exists Monadic function
⎕NGET Read Text File Ambivalent function
⎕NINFO Query or set information about one or more files and/or directories Ambivalent function
⎕NL Name List Monadic function
⎕NLOCK Lock a region of a file Ambivalent function
⎕NMOVE Move files and directories Dyadic function
⎕NNAMES Names of tied Files Constant
⎕NNUMS Tie Numbers of tied Files Constant
⎕NPARTS Split a file name into its constituent parts. Ambivalent function
⎕NPUT Write Text File Dyadic function
⎕NQ Place an event on the Queue Ambivalent function
⎕NR Nested Representation Monadic function
⎕NREAD Read from File Monadic function
⎕NRENAME Rename a File Dyadic function
⎕NREPLACE Replace data on File Dyadic function
⎕NRESIZE File Resize Dyadic function
⎕NS Namespace Ambivalent function
⎕NSI Namespace Indicator Constant
⎕NSIZE File Size Monadic function
⎕NTIE Tie a File exclusively Dyadic function
⎕NULL Null Item Variable
⎕NUNTIE Untie Files Monadic function
⎕NXLATE Specify Translation Table Ambivalent function
⎕OFF End the session Constant
⎕OPT Variant Dyadic operator
⎕OR Object Representation Monadic function
⎕PATH Search Path Variable
⎕PFKEY Programmable Function Keys Ambivalent function
⎕PP Print Precision Variable
⎕PROFILE Profile Application Ambivalent function
⎕R Replace Dyadic operator
⎕REFS Local References Ambivalent function
⎕RL Random Link Variable
⎕RSI Space Indicator Constant
⎕RTL Response Time Limit Variable
⎕S Search Dyadic operator
⎕SAVE Save the active WS Function
⎕SD Screen Dimensions Constant
⎕SH Execute a UNIX command or another program Monadic function
⎕SH Start a UNIX Auxiliary Processor Dyadic function
⎕SHADOW Shadow names Monadic function
⎕SHADOW Shadow names Monadic function
⎕SHELL Execute a shell command or another program Monadic function
⎕SI State Indicator Constant
⎕SIGNAL Signal event Ambivalent function
⎕SIZE Size of objects Monadic function
⎕SM Screen Map Variable
⎕SR Screen Read Ambivalent function
⎕SRC Source Monadic function
⎕STACK Report Stack Constant
⎕STATE Return State of an object Monadic function
⎕STOP Query Stop vector Monadic function
⎕STOP Set Stop vector Dyadic function
⎕SVC Query access Control Monadic function
⎕SVC Set access Control Dyadic function
⎕SVO Query degree of coupling Monadic function
⎕SVO Shared Variable Offer Dyadic function
⎕SVQ Shared Variable Query Monadic function
⎕SVR Retract offer Monadic function
⎕SVS Query Shared Variable State Monadic function
⎕TALLOC Allocate Token Range Abivalent function
⎕TALLOC Allocate Token Range Ambivalent function
⎕TC Terminal Control Constant
⎕TCNUMS Thread Child Numbers Monadic function
⎕TGET Get Tokens Ambivalent function
⎕THIS Self-reference Reference
⎕TID Current Thread Identity Constant
⎕TKILL Kill Threads Ambivalent function
⎕TNAME Current Thread Name Variable
⎕TNUMS Thread Numbers Constant
⎕TPOOL Token Pool Monadic function
⎕TPUT Put Tokens Ambivalent function
⎕TRACE Query Trace vector Monadic function
⎕TRACE Set Trace vector Dyadic function
⎕TRAP Event Trap Variable
⎕TREQ Token Requests Monadic function
⎕TS Timestamp Constant
⎕TSYNC Wait for Threads to Terminate Monadic function
⎕UCS Unicode Convert Ambivalent function
⎕USING Microsoft .NET Search Path Variable
⎕VFI Verify and Fix numeric Ambivalent function
⎕VGET Value Get Ambivalent function
⎕VR Vector Representation Monadic function
⎕VSET Value Set Ambivalent function
⎕WA Workspace Available Constant
⎕WC Create GUI object Ambivalent function
⎕WG Get GUI object properties Ambivalent function
⎕WN Query GUI object Names Ambivalent function
⎕WS Set GUI object properties Ambivalent function
⎕WSID Workspace Identification Variable
⎕WX Expose GUI property names Variable
⎕XML XML Convert Ambivalent function
⎕XSI Extended State Indicator Constant
⎕XT Query External variable Monadic function
⎕XT Associate External variable Dyadic function