Tcl_GetInt,  Tcl_GetDouble,  Tcl_GetBoolean - convert from
       string to integer, double, or boolean


       #include <tcl.h>

       Tcl_GetInt(interp, string, intPtr)

       Tcl_GetDouble(interp, string, doublePtr)

       Tcl_GetBoolean(interp, string, boolPtr)


       Tcl_Interp   *interp      (in)      Interpreter to use for
                                           error reporting.

       char         *string      (in)      Textual  value  to  be

       int          *intPtr      (out)     Points  to  place   to
                                           store   integer  value
                                           converted from string.

       double       *doublePtr   (out)     Points   to  place  to
                                           store double-precision
                                           floating-point   value
                                           converted from string.

       int          *boolPtr     (out)     Points   to  place  to
                                           store boolean value (0
                                           or  1)  converted from


       These procedures convert from strings to integers or  dou­
       ble-precision  floating-point  values  or booleans (repre­
       sented as 0- or 1-valued integers).  Each  of  the  proce­
       dures  takes a string argument, converts it to an internal
       form of a particular type, and stores the converted  value
       at  the  location indicated by the procedure's third argu­
       ment.  If all goes well, each of  the  procedures  returns
       TCL_OK.   If string doesn't have the proper syntax for the
       desired type then TCL_ERROR is returned, an error  message
       is left in the interpreter's result, and nothing is stored
       at *intPtr or *doublePtr or *boolPtr.
       integer  digits, optionally signed and optionally preceded
       by white space.  If the first two characters of string are
       ``0x''  then string is expected to be in hexadecimal form;
       otherwise, if the first character of string is ``0''  then
       string is expected to be in octal form;  otherwise, string
       is expected to be in decimal form.

       Tcl_GetDouble expects string to  consist  of  a  floating-
       point  number, which is:  white space;  a sign; a sequence
       of digits;  a decimal point;  a sequence of  digits;   the
       letter  ``e'';  and a signed decimal exponent.  Any of the
       fields may be  omitted,  except  that  the  digits  either
       before  or  after the decimal point must be present and if
       the ``e'' is present then it must be followed by the expo­
       nent number.

       Tcl_GetBoolean  expects string to specify a boolean value.
       If string is any of 0, false, no, or  off,  then  Tcl_Get­
       Boolean stores a zero value at *boolPtr.  If string is any
       of 1, true, yes, or on, then 1 is stored at *boolPtr.  Any
       of   these  values  may  be  abbreviated,  and  upper-case
       spellings are also acceptable.


       boolean, conversion, double, floating-point, integer