do...until

Loops through a block of PSL code until an expression is evaluated as TRUE

Syntax

do{
{ BLOCK }
} until ( expression );

Parameters

Parameter	Definition
BLOCK	one or more PSL statements that are repeatedly executed until the evaluation of expression is TRUE
expression	PSL statement where the evaluation returns either TRUE or FALSE If TRUE, the loop terminates.

Description

The PSL do...until loop behaves similarly to the C do...while loop construct in that it tests the termination condition at the end of the loop after making each pass through the body of the loop. Therefore, the body is always executed at least once. At first pass, the BLOCK of statements is executed, then expression is evaluated. If expression is FALSE, the BLOCK of statements is executed again. Iteration repeats until expression is TRUE.

The following example demonstrates the PSL do...until loop:

i = 10;
do {
printf(" %d seconds to go\n",i);
i--;
sleep(1);
} until ( i == 0);

This example produces the following output:

10 seconds to go
9 seconds to go
8 seconds to go
7 seconds to go
6 seconds to go
5 seconds to go
4 seconds to go
3 seconds to go
2 seconds to go
1 seconds to go

Where to go from here

PSL-Statements