SHARED: Difference between revisions
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The '''SHARED''' statement allows variables to be passed automatically to any [[SUB]] or [[FUNCTION]] procedure. | The '''SHARED''' statement allows variables to be passed automatically to any [[SUB]] or [[FUNCTION]] procedure. | ||
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* [[DIM]]ensioned variables are shared with all procedures in the program module. | * [[DIM]]ensioned variables are shared with all procedures in the program module. | ||
* When used with [[DIM]] in the main module, it eliminates the need to pass a parameter variable to a [[SUB]] or [[FUNCTION]]. | * When used with [[DIM]] in the main module, it eliminates the need to pass a parameter variable to a [[SUB]] or [[FUNCTION]]. | ||
* Use [[COMMON SHARED]] to share a list of variable values with sub-procedures or other modules. See also: [[COMMON]] | * Use [[COMMON SHARED]] to share a list of variable values with sub-procedures or other modules. See also: [[COMMON]] | ||
* SHARED ('''without [[DIM]]''') can share a list of variables inside of [[SUB]] or [[FUNCTION]] procedures with the main module only. | * SHARED ('''without [[DIM]]''') can share a list of variables inside of [[SUB]] or [[FUNCTION]] procedures with the main module only. | ||
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''Example 1:'' Defining variable types with [[AS]] or type suffixes. | ''Example 1:'' Defining variable types with [[AS]] or type suffixes. | ||
{{CodeStart}} | {{CodeStart}} | ||
{{Cl|DIM}} {{Cl|SHARED}} Qt AS {{Cl|STRING}} * 1, price AS {{Cl|DOUBLE}}, ID AS {{Cl|INTEGER}} | {{Cl|DIM}} {{Cl|SHARED}} Qt AS {{Cl|STRING}} * 1, price AS {{Cl|DOUBLE}}, ID AS {{Cl|INTEGER}} | ||
{{Cl|DIM}} {{Cl|SHARED}} Q$, prices#, IDs% | {{Cl|DIM}} {{Cl|SHARED}} Q$, prices#, IDs% | ||
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''Example 2:'' The DIR$ function returns a filename or a list when more than one exist. The file spec can use a path and/or wildcards. | ''Example 2:'' The DIR$ function returns a filename or a list when more than one exist. The file spec can use a path and/or wildcards. | ||
{{CodeStart}} | {{CodeStart}} | ||
{{Cl|FOR...NEXT|FOR}} i = 1 {{Cl|TO}} 2 | {{Cl|FOR...NEXT|FOR}} i = 1 {{Cl|TO}} 2 | ||
{{Cl|LINE INPUT}} "Enter a file spec: ", spec$ | {{Cl|LINE INPUT}} "Enter a file spec: ", spec$ | ||
file$ = DIR$(spec$) 'use a file spec ONCE to find the last file name listed | file$ = DIR$(spec$) 'use a file spec ONCE to find the last file name listed | ||
{{Cl|PRINT}} DIRCount%, file$, 'function can return the file count using SHARED variable | {{Cl|PRINT}} DIRCount%, file$, 'function can return the file count using SHARED variable | ||
{{Cl|DO}} | {{Cl|DO}} | ||
K$ = {{Cl|INPUT$}}(1) | K$ = {{Cl|INPUT$}}(1) | ||
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Index% = 0: DirList$(Index%) = "": ff% = {{Cl|FREEFILE}} | Index% = 0: DirList$(Index%) = "": ff% = {{Cl|FREEFILE}} | ||
{{Cl|OPEN}} TmpFile$ {{Cl|FOR (file statement)|FOR}} {{Cl|APPEND}} {{Cl|AS}} #ff% | {{Cl|OPEN}} TmpFile$ {{Cl|FOR (file statement)|FOR}} {{Cl|APPEND}} {{Cl|AS}} #ff% | ||
size& = {{Cl|LOF}}(ff%) | size& = {{Cl|LOF}}(ff%) | ||
{{Cl|CLOSE}} #ff% | {{Cl|CLOSE}} #ff% | ||
{{Cl|IF}} size& = 0 {{Cl|THEN}} {{Cl|KILL}} TmpFile$: {{Cl|EXIT FUNCTION}} | {{Cl|IF}} size& = 0 {{Cl|THEN}} {{Cl|KILL}} TmpFile$: {{Cl|EXIT FUNCTION}} | ||
{{Cl|OPEN}} TmpFile$ {{Cl|FOR (file statement)|FOR}} {{Cl|INPUT (file mode)|INPUT}} {{Cl|AS}} #ff% | {{Cl|OPEN}} TmpFile$ {{Cl|FOR (file statement)|FOR}} {{Cl|INPUT (file mode)|INPUT}} {{Cl|AS}} #ff% | ||
{{Cl|DO}} {{Cl|WHILE}} {{Cl|NOT}} {{Cl|EOF}}(ff%) {{Cl|AND (boolean)|AND}} Index% < ListMAX% | {{Cl|DO}} {{Cl|WHILE}} {{Cl|NOT}} {{Cl|EOF}}(ff%) {{Cl|AND (boolean)|AND}} Index% < ListMAX% | ||
Index% = Index% + 1 | Index% = Index% + 1 | ||
{{Cl|LINE INPUT (file statement)|LINE INPUT}} #ff%, DirList$(Index%) | {{Cl|LINE INPUT (file statement)|LINE INPUT}} #ff%, DirList$(Index%) | ||
{{Cl|LOOP}} | {{Cl|LOOP}} | ||
DIRCount% = Index% 'SHARED variable can return the file count | DIRCount% = Index% 'SHARED variable can return the file count | ||
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{{Cl|KILL}} TmpFile$ | {{Cl|KILL}} TmpFile$ | ||
{{Cl|ELSE}} {{Cl|IF}} Index% > 0 {{Cl|THEN}} Index% = Index% - 1 'no spec sends next file name | {{Cl|ELSE}} {{Cl|IF}} Index% > 0 {{Cl|THEN}} Index% = Index% - 1 'no spec sends next file name | ||
{{Cl|END IF}} | {{Cl|END IF}} | ||
DIR$ = DirList$(Index%) | DIR$ = DirList$(Index%) | ||
{{Cl|END FUNCTION}} | {{Cl|END FUNCTION}} | ||
{{CodeEnd}}{{ | {{CodeEnd}} | ||
{{Small|Code by Ted Weissgerber}} | |||
: ''Explanation:'' The SHARED variable value ''DIRcount%'' can tell the main program how many files were found using a wildcard spec. | : ''Explanation:'' The SHARED variable value ''DIRcount%'' can tell the main program how many files were found using a wildcard spec. | ||
{{PageSeeAlso}} | |||
* [[DIM]], [[REDIM]] | * [[DIM]], [[REDIM]] | ||
* [[COMMON]], [[COMMON SHARED]] | * [[COMMON]], [[COMMON SHARED]] | ||
Latest revision as of 22:48, 11 February 2023
The SHARED statement allows variables to be passed automatically to any SUB or FUNCTION procedure.
Syntax
- DIM SHARED Qt AS STRING * 1
- DIMensioned variables are shared with all procedures in the program module.
- When used with DIM in the main module, it eliminates the need to pass a parameter variable to a SUB or FUNCTION.
- Use COMMON SHARED to share a list of variable values with sub-procedures or other modules. See also: COMMON
- SHARED (without DIM) can share a list of variables inside of SUB or FUNCTION procedures with the main module only.
- Note: SHARED variables in sub-procedures will not be passed to other sub-procedures, only the main module.
Example 1: Defining variable types with AS or type suffixes.
DIM SHARED Qt AS STRING * 1, price AS DOUBLE, ID AS INTEGER DIM SHARED Q$, prices#, IDs% |
Example 2: The DIR$ function returns a filename or a list when more than one exist. The file spec can use a path and/or wildcards.
FOR i = 1 TO 2 LINE INPUT "Enter a file spec: ", spec$ file$ = DIR$(spec$) 'use a file spec ONCE to find the last file name listed PRINT DIRCount%, file$, 'function can return the file count using SHARED variable DO K$ = INPUT$(1) file$ = DIR$("") 'use an empty string parameter to return a list of files! PRINT file$, LOOP UNTIL LEN(file$) = 0 'file list ends with an empty string NEXT END FUNCTION DIR$ (spec$) CONST TmpFile$ = "DIR$INF0.INF", ListMAX% = 500 'change maximum to suit your needs SHARED DIRCount% 'returns file count if desired STATIC Ready%, Index%, DirList$() IF NOT Ready% THEN REDIM DirList$(ListMax%): Ready% = -1 'DIM array first use IF spec$ > "" THEN 'get file names when a spec is given SHELL _HIDE "DIR " + spec$ + " /b > " + TmpFile$ Index% = 0: DirList$(Index%) = "": ff% = FREEFILE OPEN TmpFile$ FOR APPEND AS #ff% size& = LOF(ff%) CLOSE #ff% IF size& = 0 THEN KILL TmpFile$: EXIT FUNCTION OPEN TmpFile$ FOR INPUT AS #ff% DO WHILE NOT EOF(ff%) AND Index% < ListMAX% Index% = Index% + 1 LINE INPUT #ff%, DirList$(Index%) LOOP DIRCount% = Index% 'SHARED variable can return the file count CLOSE #ff% KILL TmpFile$ ELSE IF Index% > 0 THEN Index% = Index% - 1 'no spec sends next file name END IF DIR$ = DirList$(Index%) END FUNCTION |
- Explanation: The SHARED variable value DIRcount% can tell the main program how many files were found using a wildcard spec.
See also