diff options
Diffstat (limited to 'generic/tclLink.c')
| -rw-r--r-- | generic/tclLink.c | 146 |
1 files changed, 75 insertions, 71 deletions
diff --git a/generic/tclLink.c b/generic/tclLink.c index eb6fa76..d04db83 100644 --- a/generic/tclLink.c +++ b/generic/tclLink.c @@ -1,55 +1,53 @@ /* * tclLink.c -- * - * This file implements linked variables (a C variable that is - * tied to a Tcl variable). The idea of linked variables was - * first suggested by Andreas Stolcke and this implementation is - * based heavily on a prototype implementation provided by - * him. + * This file implements linked variables (a C variable that is tied to a + * Tcl variable). The idea of linked variables was first suggested by + * Andreas Stolcke and this implementation is based heavily on a + * prototype implementation provided by him. * * Copyright (c) 1993 The Regents of the University of California. * Copyright (c) 1994-1997 Sun Microsystems, Inc. * - * See the file "license.terms" for information on usage and redistribution - * of this file, and for a DISCLAIMER OF ALL WARRANTIES. + * See the file "license.terms" for information on usage and redistribution of + * this file, and for a DISCLAIMER OF ALL WARRANTIES. * - * RCS: @(#) $Id: tclLink.c,v 1.9 2005/07/06 15:18:01 dgp Exp $ + * RCS: @(#) $Id: tclLink.c,v 1.10 2005/07/17 21:17:43 dkf Exp $ */ #include "tclInt.h" /* - * For each linked variable there is a data structure of the following - * type, which describes the link and is the clientData for the trace - * set on the Tcl variable. + * For each linked variable there is a data structure of the following type, + * which describes the link and is the clientData for the trace set on the Tcl + * variable. */ typedef struct Link { Tcl_Interp *interp; /* Interpreter containing Tcl variable. */ - Tcl_Obj *varName; /* Name of variable (must be global). This - * is needed during trace callbacks, since - * the actual variable may be aliased at - * that time via upvar. */ + Tcl_Obj *varName; /* Name of variable (must be global). This is + * needed during trace callbacks, since the + * actual variable may be aliased at that time + * via upvar. */ char *addr; /* Location of C variable. */ int type; /* Type of link (TCL_LINK_INT, etc.). */ union { int i; double d; Tcl_WideInt w; - } lastValue; /* Last known value of C variable; used to + } lastValue; /* Last known value of C variable; used to * avoid string conversions. */ - int flags; /* Miscellaneous one-bit values; see below - * for definitions. */ + int flags; /* Miscellaneous one-bit values; see below for + * definitions. */ } Link; /* * Definitions for flag bits: * LINK_READ_ONLY - 1 means errors should be generated if Tcl * script attempts to write variable. - * LINK_BEING_UPDATED - 1 means that a call to Tcl_UpdateLinkedVar - * is in progress for this variable, so - * trace callbacks on the variable should - * be ignored. + * LINK_BEING_UPDATED - 1 means that a call to Tcl_UpdateLinkedVar is + * in progress for this variable, so trace + * callbacks on the variable should be ignored. */ #define LINK_READ_ONLY 1 @@ -69,18 +67,17 @@ static Tcl_Obj * ObjValue _ANSI_ARGS_((Link *linkPtr)); * * Tcl_LinkVar -- * - * Link a C variable to a Tcl variable so that changes to either - * one causes the other to change. + * Link a C variable to a Tcl variable so that changes to either one + * causes the other to change. * * Results: - * The return value is TCL_OK if everything went well or TCL_ERROR - * if an error occurred (the interp's result is also set after - * errors). + * The return value is TCL_OK if everything went well or TCL_ERROR if an + * error occurred (the interp's result is also set after errors). * * Side effects: - * The value at *addr is linked to the Tcl variable "varName", - * using "type" to convert between string values for Tcl and - * binary values for *addr. + * The value at *addr is linked to the Tcl variable "varName", using + * "type" to convert between string values for Tcl and binary values for + * *addr. * *---------------------------------------------------------------------- */ @@ -89,11 +86,11 @@ int Tcl_LinkVar(interp, varName, addr, type) Tcl_Interp *interp; /* Interpreter in which varName exists. */ CONST char *varName; /* Name of a global variable in interp. */ - char *addr; /* Address of a C variable to be linked - * to varName. */ - int type; /* Type of C variable: TCL_LINK_INT, etc. - * Also may have TCL_LINK_READ_ONLY - * OR'ed in. */ + char *addr; /* Address of a C variable to be linked to + * varName. */ + int type; /* Type of C variable: TCL_LINK_INT, etc. + * Also may have TCL_LINK_READ_ONLY OR'ed + * in. */ { Tcl_Obj *objPtr; Link *linkPtr; @@ -139,16 +136,16 @@ Tcl_LinkVar(interp, varName, addr, type) * None. * * Side effects: - * If "varName" was previously linked to a C variable, the link - * is broken to make the variable independent. If there was no - * previous link for "varName" then nothing happens. + * If "varName" was previously linked to a C variable, the link is broken + * to make the variable independent. If there was no previous link for + * "varName" then nothing happens. * *---------------------------------------------------------------------- */ void Tcl_UnlinkVar(interp, varName) - Tcl_Interp *interp; /* Interpreter containing variable to unlink. */ + Tcl_Interp *interp; /* Interpreter containing variable to unlink */ CONST char *varName; /* Global variable in interp to unlink. */ { Link *linkPtr; @@ -170,16 +167,16 @@ Tcl_UnlinkVar(interp, varName) * * Tcl_UpdateLinkedVar -- * - * This procedure is invoked after a linked variable has been - * changed by C code. It updates the Tcl variable so that - * traces on the variable will trigger. + * This procedure is invoked after a linked variable has been changed by + * C code. It updates the Tcl variable so that traces on the variable + * will trigger. * * Results: * None. * * Side effects: - * The Tcl variable "varName" is updated from its C value, - * causing traces on the variable to trigger. + * The Tcl variable "varName" is updated from its C value, causing traces + * on the variable to trigger. * *---------------------------------------------------------------------- */ @@ -209,18 +206,18 @@ Tcl_UpdateLinkedVar(interp, varName) * * LinkTraceProc -- * - * This procedure is invoked when a linked Tcl variable is read, - * written, or unset from Tcl. It's responsible for keeping the - * C variable in sync with the Tcl variable. + * This procedure is invoked when a linked Tcl variable is read, written, + * or unset from Tcl. It's responsible for keeping the C variable in sync + * with the Tcl variable. * * Results: - * If all goes well, NULL is returned; otherwise an error message - * is returned. + * If all goes well, NULL is returned; otherwise an error message is + * returned. * * Side effects: - * The C variable may be updated to make it consistent with the - * Tcl variable, or the Tcl variable may be overwritten to reject - * a modification. + * The C variable may be updated to make it consistent with the Tcl + * variable, or the Tcl variable may be overwritten to reject a + * modification. * *---------------------------------------------------------------------- */ @@ -240,8 +237,8 @@ LinkTraceProc(clientData, interp, name1, name2, flags) Tcl_Obj *valueObj; /* - * If the variable is being unset, then just re-create it (with a - * trace) unless the whole interpreter is going away. + * If the variable is being unset, then just re-create it (with a trace) + * unless the whole interpreter is going away. */ if (flags & TCL_TRACE_UNSETS) { @@ -259,10 +256,9 @@ LinkTraceProc(clientData, interp, name1, name2, flags) } /* - * If we were invoked because of a call to Tcl_UpdateLinkedVar, then - * don't do anything at all. In particular, we don't want to get - * upset that the variable is being modified, even if it is - * supposed to be read-only. + * If we were invoked because of a call to Tcl_UpdateLinkedVar, then don't + * do anything at all. In particular, we don't want to get upset that the + * variable is being modified, even if it is supposed to be read-only. */ if (linkPtr->flags & LINK_BEING_UPDATED) { @@ -270,8 +266,8 @@ LinkTraceProc(clientData, interp, name1, name2, flags) } /* - * For read accesses, update the Tcl variable if the C variable - * has changed since the last time we updated the Tcl variable. + * For read accesses, update the Tcl variable if the C variable has + * changed since the last time we updated the Tcl variable. */ if (flags & TCL_TRACE_READS) { @@ -301,11 +297,11 @@ LinkTraceProc(clientData, interp, name1, name2, flags) /* * For writes, first make sure that the variable is writable. Then - * convert the Tcl value to C if possible. If the variable isn't - * writable or can't be converted, then restore the varaible's old - * value and return an error. Another tricky thing: we have to save - * and restore the interpreter's result, since the variable access - * could occur when the result has been partially set. + * convert the Tcl value to C if possible. If the variable isn't writable + * or can't be converted, then restore the varaible's old value and return + * an error. Another tricky thing: we have to save and restore the + * interpreter's result, since the variable access could occur when the + * result has been partially set. */ if (linkPtr->flags & LINK_READ_ONLY) { @@ -384,12 +380,12 @@ LinkTraceProc(clientData, interp, name1, name2, flags) * * ObjValue -- * - * Converts the value of a C variable to a Tcl_Obj* for use in a - * Tcl variable to which it is linked. + * Converts the value of a C variable to a Tcl_Obj* for use in a Tcl + * variable to which it is linked. * * Results: - * The return value is a pointer to a Tcl_Obj that represents - * the value of the C variable given by linkPtr. + * The return value is a pointer to a Tcl_Obj that represents the value + * of the C variable given by linkPtr. * * Side effects: * None. @@ -424,10 +420,18 @@ ObjValue(linkPtr) return Tcl_NewStringObj(p, -1); /* - * This code only gets executed if the link type is unknown - * (shouldn't ever happen). + * This code only gets executed if the link type is unknown (shouldn't + * ever happen). */ default: return Tcl_NewStringObj("??", 2); } } + +/* + * Local Variables: + * mode: c + * c-basic-offset: 4 + * fill-column: 78 + * End: + */ |