|
HWN( ) |
Highest Unused Window Number |
HWN(chan[,ERR=stmtref])
Where:
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chan |
Channel or logical file number of the terminal device whose highest unused window number is to be reported (usually device (0) or the console). |
|
stmtref |
Program line number or statement label to which to transfer control. |
Highest unused window number.
The HWN( ) function returns an integer, reporting the highest unused window number for a given file. If all window numbers are in use, this function will return -1. If the file is not open or not a terminal, PxPlus returns Error #13: File access mode invalid.
You can use the window number returned by the function in a subsequent 'WINDOW' mnemonic to create a new window. If no window number is passed to the 'WINDOW' mnemonic, it will utilize the lowest unused window number.
The maximum number of windows allowed on a terminal device is 250.