| System Functions |
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| Format | 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. | |
| Returns | Highest unused window number | |
| Description | 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, ProvideX 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. |
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| *Note* | The HWN( ) function is affected by your setting for the 'B0' System Parameter. | |