HP OpenVMS Systems Documentation
For complete information on installing shared libraries, refer to your operating system documentation.
When you link your program with a shared library, all symbols must be referenced before ld searches the shared library, so you should always specify libraries at the end of the cobol command line after all file names. Unless you specify the -non_shared flag, shared libraries will be searched before the corresponding archive libraries.
For instance, the following command generates an error if the file rest.o references routines in the library libX :
% cobol -call_shared test.cob -lX rest.o
The correct order follows:
% cobol -call_shared test.cob rest.o -lX
Link errors can occur with symbols that are defined twice, as when both an archive and shared object are specified on the same command line. In general, specify any archive libraries after the last file name, followed by any shared libraries at the end of the command line.
Before you reference a shared library at run time, it must be installed.
126.96.36.199 Interpreting Messages from the Linker
If the linker detects any errors while linking object modules, it displays messages about their cause and severity. If any errors occur, the linker does not produce an image file.
The message-text may be on multiple lines and is sometimes accompanied by a cobol error.
If an error occurs when you link modules, you may be able to correct it
by retyping the command string and specifying the correct routines or
dir flag), or specify the object library or object modules on
the command line.
1.1.4 Running an HP COBOL Program on Tru64 UNIX
In addition to normal IO accesses, your HP COBOL programs can read
command-line arguments and access (read and write) environment
188.8.131.52 Accessing Command-Line Arguments
Command-line arguments allow you to provide information to a program at run time. Your program provides the logic to parse the command line, identify command-line options, and act upon them. For example, you might develop a program that will extract a given amount of data from a specified file, where both the number of records to read and the file name are highly dynamic, changing for each activation of your program. In this case your program would contain code that reads a command-line argument for the number of records to read, and a second argument for the file specification. Your program execution command could look like the following:
% myprog 1028 powers.dat
In the preceding example the program myprog would read 1028 records from the file powers.dat.
Multiple command-line arguments are delimited by spaces, as shown in the preceding example. If an argument itself contains spaces, enclose that argument in quotation marks (" ") as follows:
% myprog2 "all of this is argument 1" argument2
You provide definitions for the command-line arguments with the
SPECIAL-NAMES paragraph in your program's Environment Division, and you
include ACCEPT and DISPLAY statements in the Procedure Division to
parse the command line and access the arguments. Detailed information
about command-line argument capability is in the ACCEPT and DISPLAY
sections in the HP COBOL Reference Manual.
184.108.40.206 Accessing Environment Variables
You can read and write environment variables at run time through your HP COBOL program.
Example 1-1 allows you to specify a file specification by putting the directory in the value of the environment variable COBOLPATH, and the file name in a command-line argument:
|Example 1-1 Accessing Environment Variables and Command-Line Arguments|
identification division. PROGRAM-ID. MYPROG. ENVIRONMENT DIVISION. CONFIGURATION SECTION. SPECIAL-NAMES. SYSERR IS STANDARD-ERROR ENVIRONMENT-NAME IS NAME-OF-ENVIRONMENT-VARIABLE ENVIRONMENT-VALUE IS ENVIRONMENT-VARIABLE ARGUMENT-NUMBER IS POS-OF-COMMAND-LINE-ARGUMENT ARGUMENT-VALUE IS COMMAND-LINE-ARGUMENT. DATA DIVISION. WORKING-STORAGE SECTION. 01 howmany-records PIC 9(5). 01 env-dir PIC x(50). 01 file-name PIC x(50). 01 file-spec PIC x(100). PROCEDURE DIVISION. BEGIN. ACCEPT howmany-records FROM COMMAND-LINE-ARGUMENT ON EXCEPTION DISPLAY "No arguments specified" UPON STANDARD-ERROR END-DISPLAY STOP RUN END-ACCEPT. DISPLAY "COBOLPATH" UPON NAME-OF-ENVIRONMENT-VARIABLE. ACCEPT env-dir FROM ENVIRONMENT-VARIABLE ON EXCEPTION DISPLAY "Environment variable COBOLPATH is not set" UPON STANDARD-ERROR END-DISPLAY NOT ON EXCEPTION ACCEPT file-name FROM COMMAND-LINE-ARGUMENT ON EXCEPTION DISPLAY "Attempt to read beyond end of command line" UPON STANDARD-ERROR END-DISPLAY NOT ON EXCEPTION STRING env-dir "/" file-name delimited by " " into file-spec DISPLAY "Would have read " howmany-records " records from " file-spec END-ACCEPT END-ACCEPT.
This example requires that the following command has been executed to set an environment variable:
% setenv COBOLPATH /usr/files
When you execute the following command lines:
% cobol -o myprog myprog.cob % myprog 1028 powers.dat
The following will result: