LOF

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The LOF function is used to find the length of an OPEN file in bytes, or content length of an HTTP response.


Syntax

totalBytes& = LOF([#]fileNumber)
totalBytes& = LOF([#]httpHandle)


Description

  • For regular OPENed files:
    • LOF returns the number of bytes in an OPENed designated fileNumber. File is empty if it returns 0.
    • fileNumber is the number of the opened file. # is not required.
    • Often used to determine the number of records in a RANDOM access file.
    • Can also be used to avoid reading an empty file, which would create an error.
    • LOF in QB64 can return up to 9 GB (9,223,372,036 bytes) file sizes.
  • For HTTP handles opened using _OPENCLIENT:
    • LOF returns the length listed in the Content-Length header of the HTTP response.
    • If no Content-Length header was provided on the HTTP response, then LOF return -1


Examples

Example
Finding the number of records in a RANDOM file using a TYPE variable.
  OPEN file$ FOR RANDOM AS #1 LEN = LEN(Type_variable)
  NumRecords% = LOF(1) \ RecordLEN%

Example
Reading the Content length of an HTTP response
$UNSTABLE:HTTP
h& = _OPENCLIENT("HTTP:https://qb64phoenix.com")
PRINT LOF(h&)


See also



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