Tcl_SubstObj(3) 					      Tcl Library Procedures						   Tcl_SubstObj(3)

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NAME

       Tcl_SubstObj - perform substitutions on Tcl objects

SYNOPSIS

       #include <tcl.h>

       Tcl_Obj *
       Tcl_SubstObj(interp, objPtr, flags)

ARGUMENTS

       Tcl_Interp *interp (in)		  Interpreter in which to execute Tcl scripts and lookup variables.  If an error occurs, the interpreter's
					  result is modified to hold an error message.

       Tcl_Obj *objPtr (in)		  A Tcl object containing the string to perform substitutions on.

       int flags (in)			  ORed combination of flag bits that specify which substitutions to  perform.	The  flags  TCL_SUBST_COM-
					  MANDS,  TCL_SUBST_VARIABLES and TCL_SUBST_BACKSLASHES are currently supported, and TCL_SUBST_ALL is pro-
					  vided as a convenience for the common case where all substitutions are desired.
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DESCRIPTION

       The Tcl_SubstObj function is used to perform substitutions on strings in the fashion of the subst command.  It gets the value of the string
       contained  in  objPtr  and  scans  it,  copying	characters and performing the chosen substitutions as it goes to an output object which is
       returned as the result of the function.	In the event of an error occurring during the execution of a command or variable substitution, the
       function returns NULL and an error message is left in interp's result.

       Three kinds of substitutions are supported.  When the TCL_SUBST_BACKSLASHES bit is set in flags, sequences that look like backslash substi-
       tutions for Tcl commands are replaced by their corresponding character.

       When the TCL_SUBST_VARIABLES bit is set in flags, sequences that look like variable substitutions for Tcl commands are replaced by the con-
       tents of the named variable.

       When the TCL_SUBST_COMMANDS bit is set in flags, sequences that look like command substitutions for Tcl commands are replaced by the result
       of evaluating that script.  Where an uncaught "continue exception" occurs during the evaluation of a command substitution, an empty  string
       is  substituted for the command.  Where an uncaught "break exception" occurs during the evaluation of a command substitution, the result of
       the whole substitution on objPtr will be truncated at the point immediately before the start of the command substitution, and no characters
       will be added to the result or substitutions performed after that point.

SEE ALSO

       subst(n)

KEYWORDS

       backslash substitution, command substitution, variable substitution

Tcl									8.4							   Tcl_SubstObj(3)