Provided by: tcl9.0-doc_9.0.1+dfsg-1_all bug

NAME

       Tcl_EvalObjEx,  Tcl_EvalFile,  Tcl_EvalObjv,  Tcl_Eval,  Tcl_EvalEx,  Tcl_GlobalEval,  Tcl_GlobalEvalObj,
       Tcl_VarEval - execute Tcl scripts

SYNOPSIS

       #include <tcl.h>

       int
       Tcl_EvalObjEx(interp, objPtr, flags)

       int
       Tcl_EvalFile(interp, fileName)

       int
       Tcl_EvalObjv(interp, objc, objv, flags)

       int
       Tcl_Eval(interp, script)

       int
       Tcl_EvalEx(interp, script, numBytes, flags)

       int
       Tcl_GlobalEval(interp, script)

       int
       Tcl_GlobalEvalObj(interp, objPtr)

       int
       Tcl_VarEval(interp, part, part, ... (char *)NULL)

ARGUMENTS

       Tcl_Interp *interp (in)            Interpreter in which to execute the script.  The interpreter's  result
                                          is modified to hold the result or error message from the script.

       Tcl_Obj *objPtr (in)               A Tcl value containing the script to execute.

       int flags (in)                     OR'ed  combination  of  flag  bits  that  specify  additional options.
                                          TCL_EVAL_GLOBAL and TCL_EVAL_DIRECT are currently supported.

       const char *fileName (in)          Name of a file containing a Tcl script.

       Tcl_Size objc (in)                 The number of values in the array pointed to by objv; this is also the
                                          number of words in the command.

       Tcl_Obj **objv (in)                Points to an array of pointers to values; each value holds  the  value
                                          of a single word in the command to execute.

       int numBytes (in)                  The  number  of  bytes  in  script, not including any null terminating
                                          character.  If -1, then all characters up to the first null  byte  are
                                          used.

       const char *script (in)            Points to first byte of script to execute (null-terminated and UTF-8).

       const char *part (in)              String forming part of a Tcl script.
________________________________________________________________________________________________________________

DESCRIPTION

       The  procedures described here are invoked to execute Tcl scripts in various forms.  Tcl_EvalObjEx is the
       core procedure and is used by many of the others.  It executes the  commands  in  the  script  stored  in
       objPtr  until  either  an  error  occurs  or the end of the script is reached.  If this is the first time
       objPtr has been executed, its commands are compiled into bytecode instructions which are  then  executed.
       The  bytecodes  are saved in objPtr so that the compilation step can be skipped if the value is evaluated
       again in the future.

       The return value from Tcl_EvalObjEx (and all the other procedures described here)  is  a  Tcl  completion
       code  with  one of the values TCL_OK, TCL_ERROR, TCL_RETURN, TCL_BREAK, or TCL_CONTINUE, or possibly some
       other integer value originating in an extension.  In addition, a result value or error message is left in
       interp's result; it can be retrieved using Tcl_GetObjResult.

       Tcl_EvalFile reads the file given by fileName and evaluates its contents as a Tcl script.  It returns the
       same information as Tcl_EvalObjEx.  If the file could not be  read  then  a  Tcl  error  is  returned  to
       describe  why the file could not be read.  The eofchar for files is “\x1A” (^Z) for all platforms. If you
       require a “^Z” in code for string comparison, you can use “\x1A”, which will be safely substituted by the
       Tcl interpreter into “^Z”.

       Tcl_EvalObjv executes a single preparsed command instead of  a  script.   The  objc  and  objv  arguments
       contain  the  values  of  the  words  for  the Tcl command, one word in each value in objv.  Tcl_EvalObjv
       evaluates the command and returns a completion code and result just like Tcl_EvalObjEx.   The  caller  of
       Tcl_EvalObjv  has  to  manage  the  reference count of the elements of objv, insuring that the values are
       valid until Tcl_EvalObjv returns.

       Tcl_Eval is similar to Tcl_EvalObjEx except that the script to  be  executed  is  supplied  as  a  string
       instead of a value and no compilation occurs.  The string should be a proper UTF-8 string as converted by
       Tcl_ExternalToUtfDString or Tcl_ExternalToUtf when it is known to possibly contain upper ASCII characters
       whose  possible  combinations  might be a UTF-8 special code.  The string is parsed and executed directly
       (using Tcl_EvalObjv) instead of compiling it and executing the bytecodes.   In  situations  where  it  is
       known that the script will never be executed again, Tcl_Eval may be faster than Tcl_EvalObjEx.
        Tcl_Eval returns a completion code and result just like Tcl_EvalObjEx.

       Tcl_EvalEx is an extended version of Tcl_Eval that takes additional arguments numBytes and flags.

       Tcl_GlobalEval  and  Tcl_GlobalEvalObj are older procedures that are now deprecated.  They are similar to
       Tcl_EvalEx and Tcl_EvalObjEx except that the script is evaluated in the global namespace and its variable
       context consists of global variables only (it  ignores  any  Tcl  procedures  that  are  active).   These
       functions are equivalent to using the TCL_EVAL_GLOBAL flag (see below).

       Tcl_VarEval  takes  any number of string arguments of any length, concatenates them into a single string,
       then calls Tcl_Eval to execute that string as a Tcl command.  It returns the result of  the  command  and
       also  modifies the interpreter result in the same way as Tcl_Eval.  The last argument to Tcl_VarEval must
       be (char *)NULL to indicate the end of arguments.

FLAG BITS

       Any OR'ed combination of the following values may be used for the flags argument to  procedures  such  as
       Tcl_EvalObjEx:

       TCL_EVAL_DIRECT        This  flag  is  only used by Tcl_EvalObjEx; it is ignored by other procedures.  If
                              this flag bit is set, the script is not  compiled  to  bytecodes;  instead  it  is
                              executed directly as is done by Tcl_EvalEx.  The TCL_EVAL_DIRECT flag is useful in
                              situations  where  the contents of a value are going to change immediately, so the
                              bytecodes will not be reused in a future execution.  In this case, it is faster to
                              execute the script directly.

       TCL_EVAL_GLOBAL        If this flag is set, the script is evaluated in the global  namespace  instead  of
                              the  current  namespace and its variable context consists of global variables only
                              (it ignores any Tcl procedures that are active).

MISCELLANEOUS DETAILS

       During the processing of a Tcl command it is legal to make nested calls to evaluate other commands  (this
       is  how procedures and some control structures are implemented).  If a code other than TCL_OK is returned
       from a nested Tcl_EvalObjEx invocation, then the caller should normally return immediately, passing  that
       same  return  code  back  to  its  caller,  and  so on until the top-level application is reached.  A few
       commands, like for, will check for certain return codes, like TCL_BREAK  and  TCL_CONTINUE,  and  process
       them specially without returning.

       Tcl_EvalObjEx  keeps track of how many nested Tcl_EvalObjEx invocations are in progress for interp.  If a
       code of TCL_RETURN, TCL_BREAK, or TCL_CONTINUE is about to be returned  from  the  topmost  Tcl_EvalObjEx
       invocation  for  interp,  it  converts  the return code to TCL_ERROR and sets interp's result to an error
       message indicating that the return, break, or continue command was invoked  in  an  inappropriate  place.
       This  means  that  top-level  applications  should  never see a return code from Tcl_EvalObjEx other than
       TCL_OK or TCL_ERROR.

REFERENCE COUNT MANAGEMENT

       Tcl_EvalObjEx and Tcl_GlobalEvalObj both increment and decrement the  reference  count  of  their  objPtr
       argument;  you  must  not  pass  them  any value with a reference count of zero. They also manipulate the
       interpreter result; you must not count on the interpreter result to hold the reference count of any value
       over these calls.

       Tcl_EvalObjv may increment and decrement the reference count of any value passed via its  objv  argument;
       you  must  not  pass  any  value  with  a  reference  count  of  zero. This function also manipulates the
       interpreter result; you must not count on the interpreter result to hold the reference count of any value
       over this call.

KEYWORDS

       execute, file, global, result, script, value

Tcl                                                    8.1                                        Tcl_Eval(3tcl)