Provided by: tcl8.6-doc_8.6.9+dfsg-2_all bug

NAME

       Tcl_EvalObjEx,   Tcl_EvalFile,   Tcl_EvalObjv,   Tcl_Eval,   Tcl_EvalEx,   Tcl_GlobalEval,
       Tcl_GlobalEvalObj, Tcl_VarEval, Tcl_VarEvalVA - 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)

       int
       Tcl_VarEvalVA(interp, argList)

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)                     ORed 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.

       int objc (in)                      The number of values in the array pointed to by objPtr;
                                          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).

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

       va_list argList (in)               An argument list which must have been initialized using
                                          va_start, and cleared using va_end.
_________________________________________________________________________________________________

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 “\32” (^Z) for all platforms. If you require a “^Z” in code for string comparison,  you
       can  use  “\032” or “\u001a”, which will be safely substituted by the Tcl interpreter into
       “^Z”.

       Tcl_EvalObjv executes a single pre-parsed 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.   Note:  for
       backward  compatibility  with versions before Tcl 8.0, Tcl_Eval copies the value result in
       interp to interp->result (use is deprecated) where it can be accessed directly.
        This makes Tcl_Eval somewhat slower than Tcl_EvalEx, which does not do the copy.

       Tcl_EvalEx is an extended version of Tcl_Eval that takes additional arguments numBytes and
       flags.   For  the  efficiency  reason  given above, Tcl_EvalEx is generally preferred over
       Tcl_Eval.

       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 interp->result in the same  way  as  Tcl_Eval.
       The  last  argument  to  Tcl_VarEval  must  be  NULL  to  indicate  the  end of arguments.
       Tcl_VarEval is now deprecated.

       Tcl_VarEvalVA is the same as Tcl_VarEval except that instead of taking a  variable  number
       of arguments it takes an argument list. Like Tcl_VarEval, Tcl_VarEvalVA is deprecated.

FLAG BITS

       Any  ORed  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.

KEYWORDS

       execute, file, global, result, script, value