Examples/Files: Difference between revisions
(Examples - Working with Files) |
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lNumBytes←FileSize strFileName;iTieNum;iRet <br> | lNumBytes←FileSize strFileName;iTieNum;iRet;strELXwas <br> | ||
⍝Returns file size in bytes. If file does not exist, returns -1 <br> | ⍝Returns file size in bytes. If file does not exist, returns -1 <br> | ||
⍝Sample call: FileSize "C:/FileName.txt" <br> | ⍝Sample call: FileSize "C:/FileName.txt" <br> | ||
strELXwas←⎕ELX <br> | |||
⎕ELX←"→ErrFileSiz" ⍝On error(e.g. file not found), goto ErrFileSiz line <br> | ⎕ELX←"→ErrFileSiz" ⍝On error(e.g. file not found), goto ErrFileSiz line <br> | ||
iTieNum←strFileName ⎕NTIE 0 ⍝Open file as if for reading, obtain tie number <br> | iTieNum←strFileName ⎕NTIE 0 ⍝Open file as if for reading, obtain tie number <br> | ||
lNumBytes←⎕NSIZE iTieNum ⍝Read in file size, normal operation, file found <br> | lNumBytes←⎕NSIZE iTieNum ⍝Read in file size, normal operation, file found <br> | ||
iRet←⎕NUNTIE iTieNum ⍝Finished with file read, close/untie file # <br> | iRet←⎕NUNTIE iTieNum ⍝Finished with file read, close/untie file # <br> | ||
⎕ELX←strELXwas ⍝Reset error execute function - to its entrant value. Note default initial value: ⎕ELX←"⎕DM" <br> | |||
→0 <br> | →0 <br> | ||
ErrFileSiz: lNumBytes←-1 ⍝On error, program branches here; sets # bytes found to -1 <br> | ErrFileSiz: lNumBytes←-1 ⍝On error, program branches here; sets # bytes found to -1 <br> | ||
⎕ELX←strELXwas ⍝Reset error execute function - to its entrant value. Note default initial value: ⎕ELX←"⎕DM" <br> | |||
→0 | →0 <br> | ||
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APL concepts demonstrated: '''Branching, Commenting, Exiting a Function, System Functions, use of Local Variables, Error Trapping'''. | |||
<hr align="center" color="gray" size="2" width="80%"> | <hr align="center" color="gray" size="2" width="80%"> | ||
<br> | <br> | ||
See Also: [[System_Function_NNAMES#.E2.8E.95NNAMES|System Functions - Quad NNames]], [[System_Variable_ELX|Quad ELX]] | See Also: [[System_Function_NNAMES#.E2.8E.95NNAMES|System Functions - Quad NNames]], [[System_Variable_ELX|Quad ELX]] | ||
Latest revision as of 11:54, 26 January 2015
- → Examples - Go back to examples
Example 1 - NARS2000 User APL Function: FileSize Uses System Functions/Variables: ⎕NTIE ⎕NSIZE ⎕NUNTIE ⎕ELX
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lNumBytes←FileSize strFileName;iTieNum;iRet;strELXwas |
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APL concepts demonstrated: Branching, Commenting, Exiting a Function, System Functions, use of Local Variables, Error Trapping.
See Also: System Functions - Quad NNames, Quad ELX
