Tag Archives: source file

Configuration Terms

Posted on by vivaclipper

Application :

A program designed to execute a set of interrelated tasks. Typically referring to a system designed to address a particular business purpose (e.g., Order Entry/Inventory/Invoicing, a document tracking database, or an insurance claims calculator).

Environment Variables :

Operating system variables that can be used to communicate configuration information to executable programs. Environment variables are manipulated using the DOS SET command. The Clipper language compiler and linker respond to certain environment variables. Clipper programs can inspect the settings of environment variables using the GETENV() function.

Executable File :

A file output from the linker directly executable from the operating system command line. Executable files have an .EXE extension.

See Also: Linker

Header File :

A source file containing manifest constant definitions; command or pseudofunctions; and/or program statements merged into another source file using the #include preprocessor directive.

See Also: Program File, Source Code, STD.CH

Library File :

A file containing one or more object modules. The linker searches specified libraries to resolve references to functions or procedures that were not defined in the object files being linked.

See Also: Linker, Module, Object File

Make File :

A text file used as input to a make utility containing the specifications and actions required to build a program or a system of programs. This file is often referred to as a description file.

See Also: Make

Object File :

A file that contains the output of a compiler or other language translator, generally the result of compiling a single source file. Object files are linked to create an executable program.

See Also: Linking, Program File

Procedure File :

An ASCII text file containing Clipper language procedure and function definitions usually ending with a (.prg) extension; a program file.

See Also: Program File

Program File :

An ASCII text file containing Clipper language source code. Program files usually end with a (.prg) extension. The compiler reads the program file, translates the source code, and produces an object file, that is then linked to produce an executable program.

See Also: Linking Object File Source Code

Script File :

A text file that contains command input to a compiler, linker, or other utility program. A script file is often used in lieu of equivalent keyboard input. For the Clipper compiler, script files contain a list of source files to be compiled into a single object file.

Source File :

A text file including source code.

See Also: Program File, Header File

#include directive

Posted on by vivaclipper

What is #include directive ?

#include

Include a file into the current source file

Syntax :

#include “<headerFileSpec>”

Arguments

<headerFileSpec> specifies the name of another source file to include in the current source file. As indicated in the syntax,  the name must be enclosed in double quotation marks.

<headerFileSpec> may contain an explicit path and file name as well as a file extension. If, however, no path is specified,  the preprocessor searches the following places:

. Source file directory

. Directories supplied with the /I option

. Directories specified in the INCLUDE environment variable

#include directives may be nested up to 15 levels deep–that is, a file that has been included may contain #include  directives, up to 15 levels.

Description

#include inserts the contents of the specified file in place of the #include directive in the source file. By convention, the file inserted is referred to as a header file. Header files should contain only preprocessor directives and external declarations. By convention header files have a .ch extension.

When deciding where to locate your header files, you have two basic choices. You can place them in the source file directory where they are local to the current system; or, you can make them globally available by placing them in the directory specified in the INCLUDE environment variable. A list of one or more directories can be specified.

Header files overcome the one major drawback of defining constants or inline functions–the #define directive only affects the file in which it is contained. This means that every program which needs access to these statements must have a list of  directives at the top. The solution to this problem is to place #define statements in a separate file and use the #include directive to tell the preprocessor to include that file before compiling.

For example, suppose the file “Inkey.ch” contains a list of #define directives assigning key values to constants. Instead of including these directives at the top of each program file (.prg) requiring access to them, you can simply place the following line at the top of each program file:

#include “Inkey.ch”

This causes the preprocessor to look for Inkey.ch and place all the directives contained within it at the top of this program.

Another advantage of using the #include directive is that all the #define statements are contained in one file. If any modifications to these statements are necessary, only the #include file need be altered; the program itself remains untouched.

Note that the scope of definitions within an included header file is the current program file unless the header file is included on the compiler command line with the /U option. In this case, the scope is all the program files compiled in the current invocation of the compiler.

Notes

Supplied header files: The compiler provides a number of header files containing manifest constants for common operations.

Std.ch–the standard header file: Std.ch is the standard header file provided with compiler. Std.ch contains the definitions of all compiler commands and the standard functions specified as pseudofunctions. It is strongly recommended that no changes be made to Std.ch. If changes are desired, it is advisable to copy Std.ch to a new name, make the changes, and compile with /U.

This header file differs somewhat from a header file you might #include in that everything defined in Std.ch, with #define, #translate, or #command, has a scope of the entire compile rather than the current source file.

Examples

This example uses #include to insert Inkey.ch, a file of common keyboard definitions, into a key exception handler called by an interface function:

#include "Inkey.ch"
FUNCTION GetEvent()
   LOCAL nKey, nResult
   nKey = INKEY(0)
   DO CASE
      CASE nKey = K_F10
         nResult := DoMenu("Browse")
      CASE nKey = K_ESC
         nResult := DoQuit()
      .
      . <statements>
      .
      CASE nKey = K_CTRL_RIGHT
          nResult := DoNextRec()
   ENDCASE

RETURN nResult