A virtual tape library (VTL) is a technology for data backup and recovery that uses tape libraries or tape drives along with their existing software for backup.The virtual tape library system emulates the former magnetic tape devices and data formats, but performs much faster data backups and recovery. It is able to avoid the data streaming...
Preprocessor directives are lines included in a program that being with the character #, which make them different from a typical source code text. They are invoked by the compiler to process some programs before compilation. Preprocessor directives change the text of the source code and the result is a new source code without these directives. Although preprocessing in C# is conceptually similar to that in C/C++, it is different in two aspects. First, preprocessing in C# does not involve a separate step for preprocessor execution before compilation. It is processed as a part of the lexical analysis phase. Second, it cannot be used to create macros. In addition, the new directives #region and #unregion have been added in C# along with the exclusion of some directives used earlier (#include is a notable directive whose use is replaced with "using" to include assemblies). Java does not support preprocessor directives.
A preprocessor directive is usually placed in the top of the source code in a separate line beginning with the character "#", followed by directive name and an optional white space before and after it. Because a comment on the same line of declaration of the preprocessor directive has to be used and cannot scroll through the following line, delimited comments cannot be used. A preprocessor directive statement must not end with a semicolon (;). Preprocessor directives can be defined in source code or in the common line as argument during compilation. Examples for preprocessing directives that can be used in C# include:
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