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46 lines
1.8 KiB
Markdown
46 lines
1.8 KiB
Markdown
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The [CVL](CVL) function decodes a 4-byte [STRING](STRING) generated by [MKL$](MKL$) (or read from a file) to [LONG](LONG) numeric values.
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## Syntax
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> result& = [CVL](CVL)(stringData$)
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## Description
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* *CV* functions ([CVD](CVD), [CVS](CVS), [CVI](CVI), [CVL](CVL), [CVDMBF](CVDMBF), [CVSMBF](CVSMBF)) are used to convert values encoded by *MK$* functions ([MKD$](MKD$), [MKS$](MKS$), [MKI$](MKI$), [MKL$](MKL$), [MKDMBF$](MKDMBF$), [MKSMBF$](MKSMBF$)).
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* **QB64** has [_CV](_CV) and [_MK$](_MK$) functions which can also deal with extended [Data types](Data-types).
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* [LONG](LONG) values can range from -2147483648 to 2147483647.
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* Doesn't return [_UNSIGNED](_UNSIGNED) values.
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## Example(s)
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*Example 1: 4 byte [ASCII](ASCII) character strings show how CVL multipliers convert [MKL$](MKL$) values into a 4 byte [LONG](LONG) value.
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```vb
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PRINT CVL(CHR$(1) + STRING$(3, 0)) 'ASC(CHR$(1)) * 1 = 1
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PRINT CVL(CHR$(0) + CHR$(1) + STRING$(2, 0)) 'ASC(CHR$(1)) * 256 = 256
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PRINT CVL(STRING$(2, 0) + CHR$(1) + CHR$(0)) 'ASC(CHR$(1)) * 256 * 256 = 65536
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PRINT CVL(STRING$(3, 0) + CHR$(1)) 'ASC(CHR$(1)) * 256 * 256 * 256 = 16777216
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```
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*Example 2:*
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```vb
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FIELD #1, 4 AS N$, 12 AS B$...
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GET #1
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Y& = CVL(N$)
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```
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> *Explanation:* Reads a field from file #1, and converts the first four bytes (N$) into a long integer value assigned to the variable Y&.
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> Since the representation of a long number can use up to 10 ASCII characters (ten bytes), writing to a file using [MKL$](MKL$) conversion, and then reading back with the [CVL](CVL) conversion can save up to 6 bytes of storage space.
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## See Also
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* [MKD$](MKD$), [MKI$](MKI$), [MKS$](MKS$), [MKL$](MKL$), [MKDMBF$](MKDMBF$), [MKSMBF$](MKSMBF$)
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* [CVI](CVI), [CVS](CVS), [CVD](CVD), [CVDMBF](CVDMBF), [CVSMBF](CVSMBF)
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* [_CV](_CV), [_MK$](_MK$)
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