GCC.HELPCMD.D1

GCC                                                                    CMS EXEC
 
Use the GCC command to compile and assemble a C source file using the GNU C
compiler.  Then use the LOAD and START commands to run the program:
 
   gcc hello
   load hello
   start
 
The format of the GCC command is:
+----------+------------------------------------------------------------------+
| GCC      | [fn [ft|C [fm|A]]] [( [options]                                  |
|          | options:                                                         |
|          |    ASM|NOASM     CSECT|NOCSECT     KEEP|NOKEEP     LIB fn        |
|          |    OS|CMS        PARM fn                                         |
+----------+------------------------------------------------------------------+
where:
 
fn [ft [fm]]
         identifies the C source file to be compiled.  ft defaults to C and fm
         defaults to A.
 
Options:
 
ASM|NOASM
         specifies whether the ASSEMBLE output file from the C compiler is to
         be assembled or not.  ASM is the default.
 
CSECT|NOCSECT
         specifies that the blank CSECT statement produced by GCC is to be
         given a label. NOCSECT is the default.  CSECT is required only when
         building a library of C routines.
 
KEEP|NOKEEP
         specifies whether or not the assembler output files from the C
         compiler are to be kept or erased.  NOKEEP is the default.
 
LIB fn   specifies the runtime library with which the program is to be
         compiled.  GCC will link and access the appropriate disk containing
         the C header files.  Two runtime libraries are available:
 
         GCCLIB  uses only "native" CMS functions for system services.  Using
                 this library it is possible to write programs that may be
                 loaded into resident memory as extensions of the CMS nucleus.
 
                 Ensure GCCLIB is in your list of GLOBAL TXTLIBs to run your
                 compiled progam.  Type HELP GCCLIB for more information.
 
         PDPCLIB uses simulated OS functions for system services.
 
                 Ensure PDPCLIB is in your list of GLOBAL TXTLIBs to run your
                 compiled progam. Type "HELP PDPCLIB" for more information.
 
         LIB PDPCLIB is the default.
 
OS|CMS   OS is shorthand for LIB PDPCLIB.  CMS is shorthand for LIB GCCLIB.
 
PARM fn  specifies a file of type PARM containg arguments to pass to GCC.  By
         the default file 'GCC PARM *' is used.
 
Notes:
 
         1. The GCC compiler is V3.2.3 and so is missing some features modern
            code relies on.
 
         2. Both PDPCLIB and GCCLIB only implement the C90 standard. See the
            appropriate HELP files for more details
 
         3. As the GCC EXEC calls the normal VM Assembler and LOADER external
            names are limited to 8 characters. As a result when porting code
            you will often get duplicate external names. One way round this
            is to create a ".h" file that redefines the names and include
            this in each module of your project.
 
         4. The include (<xxx.h>) files are specific to to the compiler.
            This for PDPCLIB are on the GCCCMS 201 disk, those for GCCLIB
            on the GCCCMS 202. The GCC EXEC links and accesses the appropriate
            before calling the compiler.
 
 For more information on PDPCLIB and GCC see the project web site at:-
 
                   https://gccmvs.sourceforge.net/