# System Functions

PFX( ) | Return Prefix Value

## Formats

1. | Return Specific Prefix: | PFX(num)[,ERR=stmtref])
2. | Return Prefix for PGN: | PFX(PGN[,ERR=stmtref])

Where:

num | PREFIX number to use. Numeric expression.
stmtref | Program line number or statement label to which to transfer control.

## Returns

String, current value of given PREFIX.

## Description

The PFX( ) function returns the current value of your given prefix number. If no prefix has been defined, the function will return a null string. If your specific prefix has been disabled, PxPlus returns an Error #14: Invalid I/O request for file state. (Use an ERR= option to transfer control on the error.)

You can obtain the PREFIX FILE value by using PFX(-1). The PFX system variable contains the current PREFIX(0) value.

The PFX( ) function also returns the PREFIX DIRECTORY values:

Example:

> print pfx("*usr")
> C:\Users\Guest\AppData\Roaming\PxPlus

You can only retrieve entries for which you know the matching string.

## See Also

PREFIX Set File Search Rules
PFX Current Prefix Setting

## Example

4000 rem
4010 let I=-1
4020 let X$=pfx(I,err=4040)
4030 print "PREFIX("+str(I)+")=",X$
4040 if I<=8 then let I=I+1; goto 4020
4050 print "PREFIX PGN=",pfx(pgn);stop
->goto 4000
->run
PREFIX(-1)=
PREFIX(0)=\OTHER\===\\OTHER\CUST\CASHRCPT\\OTHER\CUST\MSC\\OTHER\CUST\SALES\
PREFIX(2)=\MANUALS\===\\PVX\TESTS\
PREFIX(3)=
PREFIX(4)=
PREFIX(5)=
PREFIX(6)=
PREFIX(7)=
PREFIX(8)=
PREFIX(9)=
PREFIX PGN=\OTHER\PGMS\===\\OTHER\PGMS\PVX\\OTHER\PGMS\CUST\