GnuCOBOL entry point not found

Question

I've installed GnuCOBOL 2.2 on my Ubuntu 17.04 system. I've written a basic hello world program to test the compiler.

1       IDENTIFICATION DIVISION.
2       PROGRAM-ID. HELLO-WORLD.
3      *---------------------------
4       DATA DIVISION.
5      *---------------------------
6       PROCEDURE DIVISION.
7           DISPLAY 'Hello, world!'.
8           STOP RUN.

This program is entitled HelloWorld.cbl. When I compile the program with the command

cobc HelloWorld.cbl

HelloWorld.so is produced. When I attempt to run the compiled program using

cobcrun HelloWorld

I receive the following error:

libcob: entry point 'HelloWorld' not found

Can anyone explain to me what an entry point is in GnuCOBOL, and perhaps suggest a way to fix the problem and successfully execute this COBOL program?

Ho1 · Accepted Answer · 2017-11-12T11:14:06.080

5

According to the official manual of GNUCOBOL, you should compile your code with:

cobc -x HelloWorld.cbl

then run it with

./HelloWorld

You can also read GNUCOBOL wiki page which contains some exmaples for further information.

P.S. As Simon Sobisch said, If you change your file name to HELLO-WORLD.cbl to match the program ID, the same commands that you have used will be ok:

cobc HELLO-WORLD.cbl
cobcrun HELLO-WORLD

edited Nov 12 '17 at 11:14

answered Nov 12 '17 at 07:15

Ho1

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Note: this answer is not completely correct - the `-x` will work but it isn't the "way to compile according to the official docs", see provided answer. Nonetheless: thanks for digging into the documentation and providing an answer, +1 – Simon Sobisch Nov 12 '17 at 08:07
@SimonSobisch Thank you for your description of the compile process, but I meant to show him the way to compile *his* code", not the COBOL compilation in general. I just wanted to help him compile his Hello World example in the simplest manner. – Ho1 Nov 12 '17 at 11:09
the simplest matter is to use `HelloWorld` as `PROGRAM-ID` for his specific case ;-) – Simon Sobisch Nov 12 '17 at 12:27

score 3 · Answer 2 · answered Nov 12 '17 at 08:26

Can anyone explain to me what an entry point is in GnuCOBOL, and perhaps suggest a way to fix the problem and successfully execute this COBOL program?

An entry point is a point where you may enter a shared object (this is actually more C then COBOL). GnuCOBOL generates entry points for each PROGRAM-ID, FUNCTION-ID and ENTRY. Therefore your entry point is HELLO-WORLD (which likely gets a conversion as - is no valid identifier in ANSI C - you won't have to think about this when CALLing a program as the conversion will be done internal).

Using cobcrun internally does:

search for a shared object (in your case HelloWord), as this is found (because you've generated it) it will be loaded
search for an entry point in all loaded modules - which isn't found

There are three possible options to get this working:

As mentioned in Ho1's answer: use cobc -x, the reason that this works is because you don't generate a shared object at all but a C main which is called directly (= the entry point doesn't apply at all)
preload the shared object and calling the program by its PROGRAM-ID (entry point), either manually with COB_PRE_LOAD=HelloWorld cobcrun HELLO-WORLD or through cobcrun (option available since GnuCOBOL 2.x) cobcrun -M HelloWorld HELLO-WORLD
change the PROGRAM-ID to match the source name (either rename or change the source, I'd do the second: PROGRAM-ID. HelloWorld.)

GnuCOBOL entry point not found

2 Answers2