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CALL
Call one batch program from another.
Syntax CALL [drive:][path]filename [parameters]
CALL :label [parameters] CALL internal_cmd Key: parameters Any command-line arguments.
:label Jump to a label somewhere within the current batch file. internal_cmd Any internal NT command CALLing a command in this way (rather than simply running it) will evaluate any environment variable parameters note: CALL does support network (UNC) pathnames
Passing Parameters
When calling a secondary batch file or subroutine, you will often want the routine
to manipulate some data, the data (usually a variable) should be passed as a
parameter.
Jumping to a label
A label is defined by a single colon followed by a name
As this is effectively a subroutine I always prefix the name with s_
e.g.
:s_error_trap
When you jump to a subroutine with CALL, all statements after the label are
executed until either the end of the script is reached, or a GOTO :eof command.
GOTO :eof
will return back to just after the position where
you used CALL.
Don't forget you can also pass command line arguments to the :label and
refer to these just like the parameters passed to a separate batch file.
For example
@ECHO OFF SETLOCAL CALL :s_staff SMITH 100 GOTO s_last_bit :s_staff ECHO Name is %1 ECHO Rate is %2 GOTO :eof :s_last_bit ECHO The end of the script
Returning Parameters
When a subroutine contains local variables (SETLOCAL)
you will need a method of returning values, i.e. setting a variable that is
passed back to the
calling
routine.
This is done by executing the ENDLOCAL command on the same line as a SET statement(s)
For example
@ECHO OFF SETLOCAL CALL :s_calc 200 100 ECHO %v_return% GOTO :eof :s_calc SETLOCAL SET v_sum=0 IF %1 GTR %2 SET v_sum=5 ENDLOCAL & SET v_return=%v_sum% GOTO :eof
The use of SETLOCAL and ENDLOCAL is roughly equivalent to option explicit in Visual Basic, it's use is strongly recommended.
You should
also use SETLOCAL and ENDLOCAL when passing values
from one batch file to another.
Advanced usage : CALLing internal commands
As well as running a subroutine, CALL can also be used to run any internal
command (SET, ECHO etc) and cruicially will evaluate any environment variables
passed on the same line.
Each CALL does one substitution of the variables. (You can also
do CALL CALL... for multiple substitutions)
For example
@ECHO off SETLOCAL set pc1=frodo3 set pc2=gandalf4 set pc3=ascom5 set pc4=qwerty2 set pc5=last1 ::Loop through all the PCs FOR /L %%n IN (1,1,5) DO (call :loop %%n) goto :s_next_bit :loop set v_pc_name=pc%1 :: Evaluate the PC's name CALL SET v_pc_name=%%%v_pc_name%%% echo The pc is %v_pc_name% goto :eof :s_next_bit :: continue below :: Notice that to evaluate the contents of %pc1% :: requires triple '%' symbols i.e CALL SET v_pc_name=%%%v_pc_name%%%
If Command Extensions are disabled, the
CALL command will not accept batch labels.
"My mother never saw the irony in calling me a son-of-a-bitch." - Jack
Nicholson
Related commands:
CMD - can be used to call a subsequent batch and ALWAYS
return even if errors occur.
GOTO - jump to a label or GOTO :eof
START - Start a separate window to run a specified
program or command
Equivalent Linux BASH commands:
. (dot operator) - Include (run) commands
from another file
builtin - Run a shell builtin
chroot - Run a command with a different root
directory