mirror of
https://github.com/QB64-Phoenix-Edition/QB64pe.git
synced 2024-06-29 11:40:38 +00:00
110 lines
4.4 KiB
Plaintext
110 lines
4.4 KiB
Plaintext
The [[GET #]] statement reads data from a file or port device by bytes or record positions.
|
|
|
|
|
|
{{PageSyntax}}
|
|
: [[GET #]]{{Parameter|fileNumber&}}, [{{Parameter|position}}][, {{{Parameter|targetVariable}}|{{Parameter|targetArray()}}}]
|
|
|
|
|
|
{{PageDescription}}
|
|
* {{Parameter|fileNumber&}} is the file or port number used in the [[OPEN]] AS [[BINARY]] or [[RANDOM]] statement.
|
|
* The [[INTEGER]] or [[LONG]] byte {{Parameter|position}} in a [[BINARY]] file or the record {{Parameter|position}} in a [[RANDOM]] file '''must be greater than zero'''.
|
|
* The {{Parameter|position}} can be omitted if the GET operations are consecutive based on the {{Parameter|targetVariable}} [[TYPE]] byte size.
|
|
* The {{Parameter|targetVariable}} [[Data types|type]] or [[FIELD]] ''variable'' size determines the byte size and the next {{Parameter|position}} in the file.
|
|
* The first byte position in a file is 1. <!-- giving the previous information is enough: This may require adding one to an offset value when documentation uses that position as 0. -->
|
|
* GET does not require a byte or record {{Parameter|position}} or {{Parameter|targetVariable}} (or comma) when using a [[FIELD]] statement.
|
|
* '''QB64''' can [[PUT]] the entire contents of an array to a file and later GET those contents to a {{Parameter|targetArray()}} (include brackets).
|
|
* '''GET may ignore the end of a file and return bad data. If the [[EOF]] function returns -1 after a GET operation, it indicates that the data has ended.'''
|
|
{{TextStart}} DO UNTIL {{Cb|EOF}}(1)
|
|
{{Cb|GET}} #1, , value%
|
|
IF {{Cb|NOT}}({{Cb|EOF}}(1)) THEN {{Cb|PUT}} #2, , value%
|
|
LOOP
|
|
{{TextEnd}}
|
|
|
|
|
|
{{PageExamples}}
|
|
''Example 1:'' Opening a RANDOM file using LEN to calculate and LEN = to designate the file record size.
|
|
{{CodeStart}} '' ''
|
|
{{Cl|TYPE}} variabletype
|
|
x {{Cl|AS}} {{Cl|INTEGER}}' '2 bytes
|
|
y {{Cl|AS}} {{Cl|STRING}} * 10' '10 bytes
|
|
z {{Cl|AS}} {{Cl|LONG}}' '4 bytes
|
|
{{Cl|END}} {{Cl|TYPE}}' '16 bytes total
|
|
{{Cl|DIM}} record {{Cl|AS}} variabletype
|
|
{{Cl|DIM}} newrec {{Cl|AS}} variabletype
|
|
|
|
file$ = "testrand.inf" '<<<< filename may overwrite existing file
|
|
number% = 1 '<<<<<<<<<< record number to write cannot be zero
|
|
RecordLEN% = {{Cl|LEN}}(record)
|
|
{{Cl|PRINT}} RecordLEN%; "bytes"
|
|
record.x = 255
|
|
record.y = "Hello world!"
|
|
record.z = 65535
|
|
{{Cl|PRINT}} record.x, record.y, record.z
|
|
|
|
{{Cl|OPEN}} file$ {{Cl|FOR...NEXT|FOR}} {{Cl|RANDOM}} {{Cl|AS}} #1 {{Cl|LEN}} = RecordLEN%
|
|
{{Cl|PUT}} #1, number% , record 'change record position number to add records
|
|
{{Cl|CLOSE}} #1
|
|
|
|
{{Cl|OPEN}} file$ {{Cl|FOR...NEXT|FOR}} {{Cl|RANDOM}} {{Cl|AS}} #2 {{Cl|LEN}} = RecordLEN%
|
|
NumRecords% = {{Cl|LOF}}(2) \ RecordLEN%
|
|
PRINT NumRecords%; "records"
|
|
|
|
{{Cl|GET}} #2, NumRecords% , newrec 'GET last record available
|
|
{{Cl|CLOSE}} #2
|
|
{{Cl|PRINT}} newrec.x, newrec.y, newrec.z
|
|
|
|
{{Cl|END}} '' ''
|
|
{{CodeEnd}}
|
|
{{OutputStart}} 16 bytes
|
|
255 Hello worl 65535
|
|
1 records
|
|
255 Hello worl 65535
|
|
{{OutputEnd}}
|
|
: ''Explanation:'' The byte size of the record [[TYPE]] determines the [[LOF]] byte size of the file and can determine the number of records.
|
|
: To read the last record [[GET]] the number of records. To add a record, use the number of records + 1 to [[PUT]] new record data.
|
|
|
|
|
|
''Example 2:'' Placing the contents of a numerical array into a [[BINARY]] file. You may want to put the array size at the beginning too.
|
|
{{CodeStart}} '' ''
|
|
{{Cl|DIM}} {{Cl|SHARED}} array(100) {{Cl|AS}} {{Cl|INTEGER}}
|
|
|
|
{{Cl|FOR...NEXT|FOR}} i = 1 {{Cl|TO}} 100
|
|
array(i) = i
|
|
{{Cl|NEXT}}
|
|
showme 'display array contents
|
|
|
|
{{Cl|OPEN}} "BINFILE.BIN" {{Cl|FOR...NEXT|FOR}} {{Cl|BINARY}} {{Cl|AS}} #1
|
|
|
|
{{Cl|PUT}} #1, , array()
|
|
|
|
{{Cl|ERASE}} array 'clear element values from array and display empty
|
|
showme
|
|
{{Cl|CLOSE}} #1
|
|
|
|
{{Cl|OPEN}} "BINFILE.BIN" {{Cl|FOR...NEXT|FOR}} {{Cl|BINARY}} {{Cl|AS}} #2
|
|
{{Cl|GET}} #2, , array()
|
|
{{Cl|CLOSE}} #2
|
|
showme 'display array after transfer from file
|
|
|
|
{{Cl|END}}
|
|
|
|
{{Cl|SUB}} showme
|
|
{{Cl|FOR...NEXT|FOR}} i = 1 {{Cl|TO}} 100
|
|
{{Cl|PRINT}} array(i);
|
|
{{Cl|NEXT}}
|
|
{{Cl|PRINT}} "done"
|
|
{{Cl|END SUB}} '' ''
|
|
{{CodeEnd}}
|
|
: ''Note:'' Use empty brackets in QB64 when using [[GET]] to create an array or [[PUT]] to create a [[BINARY]] data file.
|
|
|
|
|
|
{{PageSeeAlso}}
|
|
* [[PUT|PUT #]], [[SEEK]], [[SEEK (statement)]]
|
|
* [[INPUT (file statement)|INPUT #]], [[GET (TCP/IP statement)]]
|
|
* [[FIELD]], [[RANDOM]], [[BINARY]]
|
|
* [[LEN]], [[LOF]], [[EOF]]
|
|
|
|
|
|
{{PageNavigation}}
|
|
<
|