Documentation
From my personal library, The Internet

man page:

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


SYNOPSIS

       #include <tcl.h>

       int
       Tcl_GetInt(interp, string, intPtr)

       int
       Tcl_GetDouble(interp, string, doublePtr)

       int
       Tcl_GetBoolean(interp, string, boolPtr)


ARGUMENTS

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

       CONST char   *string      (in)      Textual value to be converted.

       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 con-
                                           verted from string.

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



DESCRIPTION

       These procedures convert from strings to integers  or  double-precision
       floating-point  values or booleans (represented as 0- or 1-valued inte-
       gers).  Each of the procedures 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  argument.   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.

       Tcl_GetInt expects string to consist of a collection of 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.


KEYWORDS

       boolean, conversion, double, floating-point, integer



Tcl                                                              Tcl_GetInt(3)

Man(1) output converted with man2html