# Language Reference

System Parameters |

System parameters are used at start up to define a system's operation under PxPlus. Each consists of a two-character code enclosed in single quotes. Most parameters are Boolean switches (0 or negative sign indicates Off, 1 or no sign indicates On), but some require specific values in order to be set. See Setting/Resetting Parameters below.

#### Note:
In this reference, some parameters are always described with an = equals sign to indicate that they are set (On) using non-Boolean values; e.g. 'BY'= or 'DW'=.

Most often, system parameters are set only once at the beginning of an application, typically in a start_up program; however, any system parameter can be set or reset in your software at any time, whenever required.

For related information and examples, see SET_PARAM Directive, PRM System Variable, and PRM( ) Function.

For a complete list of system parameters, see System Parameters List.

## Setting/Resetting Parameters

The SET_PARAM directive and the PxPlus *UCP utility allow you to alter the current settings of system parameters. The specific method for setting/resetting each parameter is explained with each definition.

Examples:

> SET_PARAM 'AH' Switches Alternative Heading On
> SET_PARAM -'AH' Switches Alternative Heading Off
> SET_PARAM 'AH'=0 Switches Alternative Heading Off
> SET_PARAM 'BY'=0 Sets the Base Year to Julian calendar base
> SET_PARAM 'BY'=1970 Sets Base Year to 1970

Off: Parameter shows a negative sign or is set to equal 0 (zero).
On: Parameter is not negative or is set to equal a specific value.

## Parameter Defaults

The PRM system variable can be used to return a string of the current system parameters and their values. (Some will be hidden from the PRM list unless they are actually set.)

PRINT PRM lists the following defaults in PxPlus for Windows 32-bit:

> PRINT PRM !
> -'3D',-'AD',-'AH','AI'=10,-'B0','BF'=10,-'BT',-'BX','BY'=1970,-'CD','CS',
> 'CT'=0,'CU'=36,-'D0',-'DC','DF'=0,'DL'=0,'DP'=46,'DT'=0,'DW'=0,-'EG','EL'=0,
> -'EO',-'ES',-'EX',-'F4','FB'=5,-'FC','FF'=0,-'FI','FO'=0,-'FU',-'FL','FP',
> 'FS'=138,-'FT',-'FX',-'F,',-'I0',-'I2','IC',-'IM','IR','IS'=5,-'IZ',-'KR',
> 'LB'=4,-'LC',-'LD',-'LE','LS'=1,-'LU',-'LZ','MB'=0,-'MC','MF'=50,-'MP','NE',
> -'NI',-'NK',-'NL',-'NN',-'NR',-'OC','OL'=25,'OM',-'OP','OR','OW'=0,'PC'=0,
> 'PD'=2,-'PO',-'PU','PW'=36,-'PZ','QF'=1,'Q_'=2,'Q^'=2,-'QS',-'QT',-'RI',
> 'RN'=1,'RP',-'RR',-'RS',-'SC',-'SD',-'SF',-'SK','SL'=32,-'SP',-'SR','SV'=1,
> 'SZ'=32000,-'TB','TC'=0,'TH'=44,-'TL',-'TN',-'TT',-'TU',-'TX','VP'=48,'VR'=0,
> 'VW'=0,'WB','WD'=10000,-'WF','WH'=0,'WI'=1000,-'WK','WT'=2,-'XC',-'XF',-'XI',
> -'XT',-'ZP',-'DD','!B'=3,'!U'=0,-'1U'

## Saving/Restoring System Parameters

To avoid conflicts with other software components, it is strongly recommended that you save the current settings for parameters you need to change and then reset them when done.

#### Note:
The 'BX' parameter is the only exception to this recommendation since it affects a series of system parameters. Never attempt to save/change/restore 'BX'. It should be set/reset only at the start of a session.

Example:

> 0010 sv_ex=prm('ex'); SET_PARAM -'EX'
> .....
> 9900 SET_PARAM 'EX'=sv_ex