Chapter 5. General Language Features of M

Revision History
Revision V6.0-001 21 March 2013
Revision V5.5-000/2 31 October 2012 Corrected the reference to the gtm_tprestart_log_delta and gtm_tprestart_log_first environment variables in “TP Performance”.
Revision V5.5-000/1 05 October 2012 Improved the description of “TP Characteristics” and added the guidelines for implementing Web Services safely on GT.M.
Revision V5.4-002B 26 December 2011 Conversion to documentation revision history reflecting GT.M releases with revision history for each chapter.

Table of Contents

Data Types
Numeric Expressions
Numeric Accuracy
Integer Expressions
Truth-valued Expressions
M Names
Variables
Arrays and Subscripts
M Collation Sequences
Local Variables
Global Variables and Resource Name Environments
Naked References
Global Variable Name Environments
Literals
String Literals
Numeric Literals
Expressions
Operators
Precedence
Arithmetic Operators
Logical Operators
String Operators
Numeric Relational Operators
String Relational Operators
Pattern Match Operator
Commands
Postconditionals
Timeouts
M Locks
Intrinsic Functions
Intrinsic Special Variables
Routines
Lines
Entry References
Label References
Indirection
Argument Indirection
Atomic Indirection
Entryref Indirection
Pattern Code Indirection
Name Indirection
Indirection Concerns
Parameter Passing
Actuallists
Actualnames
Formallists
Formallabel
Parameter Passing Operation
Parameter Passing Mechanisms
GT.M Parameter Passing Extensions
External Calls
Extrinsic Functions
Extrinsic Special Variables
Transaction Processing
TP Definitions
TP Characteristics
TP Performance
TP Example

This chapter describes general features of the M language, as well as general information about the operation of GT.M. Commands, Functions, and Intrinsic Special Variables are each described in separate chapters. This chapter contains information about exceptions, as well as information about general M features.

MUMPS is a general purpose language with an embedded database system. This section describes the features of the language that are not covered as Commands, Functions, or Intrinsic Special Variables chapters.