Provided by: tcl8.6-doc_8.6.1-4ubuntu1_all 
NAME
Tcl_ParseArgsObjv - parse arguments according to a tabular description
SYNOPSIS
#include <tcl.h>
int
Tcl_ParseArgsObjv(interp, argTable, objcPtr, objv, remObjv)
ARGUMENTS
Tcl_Interp *interp (out) Where to store error messages.
const Tcl_ArgvInfo *argTable (in) Pointer to array of option descriptors.
int *objcPtr (in/out) A pointer to variable holding number of
arguments in objv. Will be modified to hold
number of arguments left in the unprocessed
argument list stored in remObjv.
Tcl_Obj *const *objv (in) The array of arguments to be parsed.
Tcl_Obj ***remObjv (out) Pointer to a variable that will hold the array
of unprocessed arguments. Should be NULL if
no return of unprocessed arguments is
required. If objcPtr is updated to a non-zero
value, the array returned through this must be
deallocated using ckfree.
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DESCRIPTION
The Tcl_ParseArgsObjv function provides a system for parsing argument lists of the form
“-someName someValue ...”. Such argument lists are commonly found both in the arguments
to a program and in the arguments to an individual Tcl command. This parser assumes that
the order of the arguments does not matter, other than in so far as later copies of a
duplicated option overriding earlier ones.
The argument array is described by the objcPtr and objv parameters, and an array of
unprocessed arguments is returned through the objcPtr and remObjv parameters; if no return
of unprocessed arguments is desired, the remObjv parameter should be NULL. If any problems
happen, including if the “generate help” option is selected, an error message is left in
the interpreter result and TCL_ERROR is returned. Otherwise, the interpreter result is
left unchanged and TCL_OK is returned.
The collection of arguments to be parsed is described by the argTable parameter. This
points to a table of descriptor structures that is terminated by an entry with the type
field set to TCL_ARGV_END. As convenience, the following prototypical entries are
provided:
TCL_ARGV_AUTO_HELP
Enables the argument processor to provide help when passed the argument “-help”.
TCL_ARGV_AUTO_REST
Instructs the argument processor that arguments after “--” are to be unprocessed.
TCL_ARGV_TABLE_END
Marks the end of the table of argument descriptors.
ARGUMENT DESCRIPTOR ENTRIES
Each entry of the argument descriptor table must be a structure of type Tcl_ArgvInfo. The
structure is defined as this:
typedef struct {
int type;
const char *keyStr;
void *srcPtr;
void *dstPtr;
const char *helpStr;
ClientData clientData;
} Tcl_ArgvInfo;
The keyStr field contains the name of the option; by convention, this will normally begin
with a “-” character. The type, srcPtr, dstPtr and clientData fields describe the
interpretation of the value of the argument, as described below. The helpStr field gives
some text that is used to provide help to users when they request it.
As noted above, the type field is used to describe the interpretation of the argument's
value. The following values are acceptable values for type:
TCL_ARGV_CONSTANT
The argument does not take any following value argument. If this argument is
present, the int pointed to by the srcPtr field is copied to the dstPtr field. The
clientData field is ignored.
TCL_ARGV_END
This value marks the end of all option descriptors in the table. All other fields
are ignored.
TCL_ARGV_FLOAT
This argument takes a following floating point value argument. The value (once
parsed by Tcl_GetDoubleFromObj) will be stored as a double-precision value in the
variable pointed to by the dstPtr field. The srcPtr and clientData fields are
ignored.
TCL_ARGV_FUNC
This argument optionally takes a following value argument; it is up to the handler
callback function passed in srcPtr to decide. That function will have the following
signature:
typedef int (Tcl_ArgvFuncProc)(
ClientData clientData,
Tcl_Obj *objPtr,
void *dstPtr);
The result is a boolean value indicating whether to consume the following argument.
The clientData is the value from the table entry, the objPtr is the value that
represents the following argument or NULL if there are no following arguments at
all, and the dstPtr argument to the Tcl_ArgvFuncProc is the location to write the
parsed value to.
TCL_ARGV_GENFUNC
This argument takes zero or more following arguments; the handler callback function
passed in srcPtr returns how many (or a negative number to signal an error, in
which case it should also set the interpreter result). The function will have the
following signature:
typedef int (Tcl_ArgvGenFuncProc)(
ClientData clientData,
Tcl_Interp *interp,
int objc,
Tcl_Obj *const *objv,
void *dstPtr);
The clientData is the value from the table entry, the interp is where to store any
error messages, the keyStr is the name of the argument, objc and objv describe an
array of all the remaining arguments, and dstPtr argument to the
Tcl_ArgvGenFuncProc is the location to write the parsed value (or values) to.
TCL_ARGV_HELP
This special argument does not take any following value argument, but instead
causes Tcl_ParseArgsObjv to generate an error message describing the arguments
supported. All other fields except the helpStr field are ignored.
TCL_ARGV_INT
This argument takes a following integer value argument. The value (once parsed by
Tcl_GetIntFromObj) will be stored as an int in the variable pointed to by the
dstPtr field. The srcPtr field is ignored.
TCL_ARGV_REST
This special argument does not take any following value argument, but instead marks
all following arguments to be left unprocessed. The srcPtr, dstPtr and clientData
fields are ignored.
TCL_ARGV_STRING
This argument takes a following string value argument. A pointer to the string will
be stored at dstPtr; the string inside will have a lifetime linked to the lifetime
of the string representation of the argument value that it came from, and so should
be copied if it needs to be retained. The srcPtr and clientData fields are ignored.
SEE ALSO
Tcl_GetIndexFromObj(3tcl), Tcl_Main(3tcl), Tcl_CreateObjCommand(3tcl)
KEYWORDS
argument, parse