Comparison of User-Defined Function Features: Difference between revisions
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! rowspan="2"|Quality | ! rowspan="2"|Quality | ||
! rowspan="2"|User Defined Function | ! rowspan="2"|Normal User Defined Function | ||
! rowspan="2"|User Defined Library Function in Main Program | ! rowspan="2"|User Defined Library Function in Main Program | ||
! colspan="3"|User Defined Library Function | ! colspan="3"|User Defined Library Function in Separate Program | ||
|- | |- | ||
!Resident | !Resident | ||
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|yes | |yes | ||
|- | |- | ||
|Linkage must be | |Linkage must be established (via LIBRARY statement) before function may be called | ||
|no | |no | ||
|yes | |yes | ||
| Line 29: | Line 29: | ||
|Program may be specified in named LIBRARY statement | |Program may be specified in named LIBRARY statement | ||
|n/a | |n/a | ||
| | |no | ||
|yes | |yes | ||
|yes | |yes | ||
|yes | |yes | ||
|- | |- | ||
| | |Loaded program will be searched for function when unnamed LIBRARY statement is executed | ||
|n/a | |n/a | ||
|yes | |yes | ||
| Line 53: | Line 53: | ||
|When main program ends (Default). Other options available | |When main program ends (Default). Other options available | ||
|When main program ends | |When main program ends | ||
|When | |When function call ends | ||
|- | |- | ||
|Using OPTION RETAIN in the library program causes the library to retain global variables irrespective of when the program ends | |Using OPTION RETAIN in the library program causes the library to retain global variables irrespective of when the program ends | ||
| Line 62: | Line 62: | ||
|no | |no | ||
|- | |- | ||
|Library is loaded into | |Library is loaded into memory with the LOAD command | ||
|n/a | |n/a | ||
|n/a | |n/a | ||
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|no | |no | ||
|- | |- | ||
|Library is automatically removed from | |Library is automatically removed from memory when all function definitions are reassigned | ||
|n/a | |n/a | ||
|n/a | |n/a | ||
Latest revision as of 11:25, 16 October 2014
The following table illustrates the similarities and differences between regular user-defined functions (non-library) and library user-defined functions.
| Quality | Normal User Defined Function | User Defined Library Function in Main Program | User Defined Library Function in Separate Program | ||
|---|---|---|---|---|---|
| Resident | Present | As Needed | |||
| LIBRARY keyword required on DEF statement | no | yes | yes | yes | yes |
| Linkage must be established (via LIBRARY statement) before function may be called | no | yes | yes | yes | yes |
| Program may be specified in named LIBRARY statement | n/a | no | yes | yes | yes |
| Loaded program will be searched for function when unnamed LIBRARY statement is executed | n/a | yes | yes | yes | no |
| Main program's global variables are available to the function | no | yes | no | no | no |
| Point at which global variables are cleared | When main program ends | When main program ends | When main program ends (Default). Other options available | When main program ends | When function call ends |
| Using OPTION RETAIN in the library program causes the library to retain global variables irrespective of when the program ends | n/a | na/a | yes | no | no |
| Library is loaded into memory with the LOAD command | n/a | n/a | yes | no | no |
| Library is cleared from memory with the CLEAR command | n/a | n/a | yes | no | no |
| Library is automatically removed from memory when all function definitions are reassigned | n/a | n/a | no | yes | n/a |
| Library is automatically removed from memory when main program ends | n/a | n/a | no | yes | n/a |