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32 lines
1.4 KiB
Plaintext
32 lines
1.4 KiB
Plaintext
The [[LOCK]] statement restricts access to parts of a file by other programs or processes.
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{{PageSyntax}}
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:[[LOCK]] [#]{{Parameter|fileNumber%}}
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:[[LOCK]] [#]{{Parameter|fileNumber%}}, {{Parameter|record&}}
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:[[LOCK]] [#]{{Parameter|fileNumber%}}, [{{Parameter|firstRecord&}}] TO {{Parameter|lastRecord&}}
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{{PageDescription}}
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* {{Parameter|fileNumber%}} is the file number of the file to lock.
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* In the first syntax, the entire file is locked.
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* In the second syntax, {{Parameter|record&}} is the record number of the file to lock.
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* In the third syntax, the records or bytes in the range [{{Parameter|firstRecord&}},{{Parameter|lastRecord&}}] are locked. If {{Parameter|firstRecord&}} is omitted, it is assumed to be one (the first record or byte).
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* For files opened in [[BINARY]] mode, each record corresponds to a single byte.
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* [[LOCK]] and [[UNLOCK]] statements are always used in pairs and each statement must match the other one.
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* Files must be unlocked using [[UNLOCK]] before other programs can access them, and before the file is closed.
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* [[Keywords_currently_not_supported_by_QB64#Keywords_Not_Supported_in_Linux_or_MAC_OSX_versions|Keyword not supported in Linux or macOS versions]]
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{{PageQBasic}}
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* Required DOS '''SHARED.EXE''' to be run for QBasic to use networking access modes. No longer required.
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{{PageSeeAlso}}
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* [[UNLOCK]]
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* [[OPEN]]
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* [[ACCESS]]
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{{PageNavigation}}
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