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Using OPTLINK

This chapter describes the operational aspects of using OPTLINK.

What's in This Chapter

Operational Modes

OPTLINK's available operational modes are: command line, interactive, and indirect file. All input on the command line should be in a series of parameters. For the interactive mode at a console, use link. exe. Using indirect file operation, you can enter prompt-like responses into a file. The specific file name is passed to OPTLINK on the command line and thus read by OPTLINK for its linker input.

In all modes of operation, OPTLINK requires that you provide the same kinds of control information, in the form of OPTLINK commands. This chapter describes the methods by which your commands may be transmitted to OPTLINK.

Command Line and Interactive Operation

Command line operation of OPTLINK uses the following syntax:
	LINK obj[,out[,map[,lib[,def[,res]]]]] 
For interactive operation simply input LINK followed by any option switches, which are described later, and press Enter. OPTLINK then prompts you for responses (option switches may be entered after any response).

OPTLINK parameters include the following:

obj
One or more input (.obj) file names. If multiple names are supplied, they may be joined by "+" characters or blank spaces, but the comma separates the four parts of the command line. If more names are required than are able to fit onto the command line, a "+" immediately before the end of the line makes the list continue to the next line.

You may use ambiguous names wild-card characters "?" and "*". If specific names are preceded or followed by wild-card references, those modules specifically named will not be included twice. At the end of the input list, you may use specific data or a "+" character to invoke the default choices. If neither is supplied, operation switches to the interactive mode, and you are prompted for the remaining inputs. The "#" character tells OPTLINK to ignore the rest of the comment characters following on that line.

out
Specifies the name for the output executable or dynamic link library. If no extension is supplied, an .exe file is generated; if the extension is .com, a .com file is created automatically, and if extension is .sys, a binary device driver format file is created. To skip this entry, cause OPTLINK to default to the executable type provided in a definition file or option switch, supply a comma or press the Enter key in the interactive mode. If no directive or option switch is supplied, the default file name (that of the first .obj file) with .exe extension will be created.

map
The file name for map output. Using an Enter key while in the interactive mode suppresses all map output, unless previously configured with a /MAP suggested file name. See the related switch descriptions (/MAP, /XREF, /LINENUMBERS, or /DETAILEDMAP) later in this manual.

lib
Searches in order one or more library names to resolve any symbols not defined in the input .obj files. You may use wild card references as with the obj entry. The libraries are searched in the order specified here. You may use the same separators as you used for the obj portion apply. You may use the "+" continuation character that comes before the end-of-line or before the comment (#) string to extend past the end of the line.

The lib entry may be either a single file name or a pathname (with trailing "\") to a directory containing the libraries.

OPTLINK searches library files in the order that they are presented to it: that is, those named on the command line, and then those referenced by embedded commands in object modules. To locate each library file for which no path is specified, OPTLINK first searches the current directory followed by any paths specified in the LIB variable, and finally any paths named in the command line.

def
The definition file name. Optionally supplied, this file contains program linking information. This file type and its contents are described later in this manual.

res
One or more resource (.RES) file names. When supplied, OPTLINK performs the bind step of the Resource Compiler while linking. This eliminates the need to use a Resource Compiler to combine resources to the output file.

Also like the .OBJ entry, wild-card references may be used. The libraries will be searched in the order specified. The same separators used for the obj portion apply, and the res entry may also be extended past the end of a line by means of the continuance character (+) immediately before the end of line or comment (#) string.

Examples of command line operation

The simplest method of using OPTLINK is to provide only the name of the .obj file to be used and accept the default suggestions for all other parameters:
	C> LINK DUMP;
	OPTLINK Copyright (C) Digital Mars 1989-94 
	All rights reserved.
OPTLINK's sign-on copyright message is displayed on the console as shown above.

If the .obj file does not exist in the current directory or in any of the paths supplied by the environment variables, OPTLINK sends an error message:

	C> LINK DUMPER;
	OPTLINK Copyright (C) Digital Mars 1989-94 
	All rights reserved.
	DUMPER.OBJ 
	Error 2: File Not Found DUMPER.OBJ 
If you do not use a semicolon on a short command line, OPTLINK reverts to the interactive mode after all command line input is used, as the following examples indicate:
	C> LINK DUMP,,MYMAP;
	OPTLINK Copyright (C) Digital Mars 1989-94 
	All rights reserved. 

	C> LINK DUMP,,MYMAP
	OPTLINK Copyright (C) Digital Mars 1989-94 
	All rights reserved.
	Libraries and Paths: (.lib): 
	Definition File: (.def):
	Resource Files: (.res) 

Examples of interactive operation

Use the Enter key at the Map File: prompt.
	C> LINK
	OPTLINK Copyright (C) Digital Mars 1989-94 
	All rights reserved.
	OBJ Files: (.obj): curset 
	Output File: (curset.exe):
	Map File: (.map): 
	Libraries and Paths: (.lib):
	Definition File: (.def): 
	Resource Files: (.res) 
Using the "+" and the "#" comment characters causes multiple responses at the OBJ Files: prompt:
	C> LINK
	OPTLINK Copyright (C) Digital Mars 1989-94 
	All rights reserved.
	OBJ Files: (.obj): file1+	# this is the first object file
	OBJ Files: (.obj): file2+ 
	OBJ Files: (.obj): file3	# this is the last
	Output File: (file1.exe): myfile 
	Map File: (.map):
	Libraries and Paths: (.lib): mylib 
	Definition File: (.def):
	Resource Files: (.res) 
Or use multiple file names on the same line:
	C> LINK
	OPTLINK Copyright (C) Digital Mars 1989-94 
	All rights reserved. OBJ Files: (.obj): file1 file2 file3 
	Output File: (file1.exe): myfile
	Map File: (.map): 
	Libraries and Paths: (.lib): mylib
	Definition File: (.def): 
	Resource Files: (.res) 

Indirect File Operation

If your application requires more file names or option switches than the command line can hold, you can use indirect file operation to effectively eliminate any limit on the amount of information you can supply to OPTLINK. For most complicated applications, this is the best choice.

OPTLINK uses the following syntax for indirect file operation:

	LINK @indirfile
where indirfile is the name of an indirect response file. During interactive operation at each prompt, the indirect response file has a number of text lines.

Example of indirect file operation

If the file lnklst contains the following lines:
	DUMP
	NEWEXE 
	MYMAP; 
then the following command lines are equivalent except that line length in an indirect file is unlimited, while DOS limits the command line to a maximum of 125 characters.
	LINK @LNKLST 
	LINK DUMP,NEWEXE,MYMAP; 
It is legal to use combinations of indirect file operation and either command line or interactive operation. OPTLINK accepts more than one indirect file specification. There are only two constraints: the indirect files that are combined must result in a valid sequence of responses and cannot be nested more than 10 deep.

Note: It is possible for a valid file name to actually begin with the "@" character. To keep such a file from being erroneously recognized by OPTLINK as an indirect response file, enclose the entire name of the file in quotation marks.

Command formats

All three methods of providing command input use exactly the same format for input information.

File name usage

OPTLINK uses the same file-naming conventions as those supplied by the host operating system. If a file extension is supplied, it must be separated from the name by a period. If none is supplied, OPTLINK assumes or creates a default value as described below.

The file name may be preceded by a pathname, which may be either absolute or relative and may include a drive specifier. If no path is specified, OPTLINK searches only the current working directory for the file or creates it in the current working directory. If a drive is specified, but no path, only the current directory for the specified drive is used.

Default file extensions

If the file extension is omitted from a file name, OPTLINK assumes or creates a default extension for the file that is determined by the command with which the file name is associated. For instance, the default extensions for the file names supplied with the OBJ Files: prompt is .obj and for the Map File: prompt is .map. The defaults follow and are described later for each command that assumes or creates one. To refer to a file that has no extension and without using the default, add the "." separator after the file name to tell OPTLINK not to supply an extension.
.def
Definition file describing desired output
.exe
Executable files created by OPTLINK
.lib
Library files
.map
Listing of addresses generated by OPTLINK
.obj
Object files (in OMF format)
.cfg
Configuration file for default OPTLINK settings
.res
Resource files
none
Indirect command file used by OPTLINK

Special file names

Since OPTLINK uses standard DOS functions for keyboard input and screen output, you may use device names in place of file names and you may redirect input and output. The device names are:
AUX
refers to an auxiliary device (usually the same as COM1)
CON
refers to the console (keyboard input or display output)
PRN
refers to the printer (usually the same as LPT1) NUL a null (nonexistent) file; if given as an input name, returns end-of-file; if given as an output name, no output is generated
To redirect OPTLINK input and output from and to files, use the standard redirection keys. For example, the following command redirects OPTLINK output (including all prompts) to file link.log instead of to the screen:
	LINK UTILITY; >LINK.LOG