Compiling source code

Source code modules (with .4gl file extension) must be compiled to p-code modules (with .42m file extension) by using the fglcomp tool. Compiled p-code modules are independent from the platform and processor architecture.

The following lines show a compilation in a UNIX™ shell session:

$ cat prog.4gl
MAIN
  DISPLAY "hello"
END MAIN

$ fglcomp prog.4gl

$ ls -s prog.42m
   4 prog.42m

If an error occurs, the compiler writes an error file with the .err extension.

$ cat prog.4gl
MAIN
  LET x = "hello"
END MAIN

$ fglcomp prog.4gl
Compilation was not successful. Errors found: 1.
 The file prog.4gl has been written.

$ cat prog.err
MAIN
  LET x = "hello"
| The symbol 'x' does not represent a defined variable.
| See error number -4369. 
END MAIN

With the -M option, you can force the compiler to display an error message instead of generating an .err error file:

$ fglcomp prog.4gl
xx.4gl:2:8 error:(-4369) The symbol 'x' does not represent a defined variable.

By default, the compiler does not raise any warnings. You can turn on warnings with the -W option:

$ cat prog.4gl
MAIN
  DATABASE test1
  SELECT COUNT(*) FROM x, OUTER(y) WHERE x.k = y.k
END MAIN

$ fglcomp -W stdsql prog.4gl
xx.4gl:3: warning: SQL statement or language instruction with specific SQL syntax.

When a warning is raised, you can use the -W error option to force the compiler to stop as if an error was found. For more details about the -W option, see Arguments for the -W option.

Consider also using the --verbose option of the compiler to get detailed information about the source compilation:

$ fglcomp --verbose main.4gl
[parsing main.4gl]
[compiling: fglcomp --import-by=main --verbose  mod1]
[parsing mod1.4gl]
[compiling: fglcomp --import-by=main,mod1 --verbose  mod2]
[parsing mod2.4gl]
[writing mod2.42m]
[loading mod2.42m]
[writing mod1.42m]
[loading mod1.42m]
[writing main.42m]