How to use SAC's

Application Programmer Interface

*** How to use SAC2000's external function capability. ***


Summary: Build a shared object according to specifications 
         use load command to load into sac 
         run the command as desired 

STEP 1: compile srcs into one or more external libs.  
        For example the following loads a command called 
        flipxy into a shared object library libext.so

cc -o /us/peterg/lib/libext.so -G flipxy.c  

        By default sac will call the command flipxy.  
        Note: we can have multiple srcs on this line.
        e.g., cc -o /us/peterg/lib/libext.so -G extern.c velarr.c flipxy.c 
        See the load command for more details.  

STEP 2: Setup the SACSOLIST and LD_LIBRARY_PATH environments. 

        setenv SACSOLIST "Shared library name"
        e.g., setenv SACSOLIST libext.so   
        Use space delim and quotes for multiple libs

        setenv LD_LIBRARY_PATH ${LD_LIBRARY_PATH}:/Path_to_Shared_Library
        e.g., setenv LD_LIBRARY_PATH ${LD_LIBRARY_PATH}:/us/peterg/lib

STEP 3: {Optional}  Use init script to load automatically. 
        alias sac "/usr/local/bin/sac /us/peterg/bin/sacmac/sac.init" 
        where sac.init includes the users startup commands including 
        load external_function_command_name
        The following is an example initialization file: 
	   setmacro /us/peterg/bin/sacmac
           window 1 x .34 1.0 y 0.5 1.0
           qdp 5000
           load flipxy

STEP 4: Startup sac and load the command (if you didn't load it via STEP 3).  
        e.g.,  SAC> load flipxy 
               SAC> fg 
               SAC> flipxy


*** How to Share with other users: ***

STEP 1: Give other users your function or shared library and this notes file.  
        Tell the other users to do step 2-4.  

STEP 2: You can also send external function you would like distributed 
        as part of the SAC2000 distribution to: 

 	peterg@llnl.gov 

        Please include a brief description with a relevant references that 
        we can include as part of the documentation.  
        All contributions will be acknowledged appropriately.