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diff --git a/doc/SetVar.3 b/doc/SetVar.3 new file mode 100644 index 0000000..32e7a4c --- /dev/null +++ b/doc/SetVar.3 @@ -0,0 +1,204 @@ +'\" +'\" Copyright (c) 1989-1993 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. +'\" +'\" SCCS: @(#) SetVar.3 1.30 97/10/10 16:10:36 +'\" +.so man.macros +.TH Tcl_SetVar 3 7.4 Tcl "Tcl Library Procedures" +.BS +.SH NAME +Tcl_SetVar, Tcl_SetVar2, Tcl_GetVar, Tcl_GetVar2, Tcl_UnsetVar, Tcl_UnsetVar2 \- manipulate Tcl variables +.SH SYNOPSIS +.nf +\fB#include <tcl.h>\fR +.sp +char * +\fBTcl_SetVar\fR(\fIinterp, varName, newValue, flags\fR) +.sp +char * +\fBTcl_SetVar2\fR(\fIinterp, name1, name2, newValue, flags\fR) +.sp +char * +\fBTcl_GetVar\fR(\fIinterp, varName, flags\fR) +.sp +char * +\fBTcl_GetVar2\fR(\fIinterp, name1, name2, flags\fR) +.sp +int +\fBTcl_UnsetVar\fR(\fIinterp, varName, flags\fR) +.sp +int +\fBTcl_UnsetVar2\fR(\fIinterp, name1, name2, flags\fR) +.SH ARGUMENTS +.AS Tcl_Interp *newValue +.AP Tcl_Interp *interp in +Interpreter containing variable. +.AP char *varName in +Name of variable. +May include a series of \fB::\fR namespace qualifiers +to specify a variable in a particular namespace. +May refer to a scalar variable or an element of +an array variable. +If the name references an element of an array, then it +must be in writable memory: Tcl will make temporary modifications +to it while looking up the name. +.AP char *newValue in +New value for variable. +.AP int flags in +OR-ed combination of bits providing additional information for +operation. See below for valid values. +.AP char *name1 in +Name of scalar variable, or name of array variable if \fIname2\fR +is non-NULL. +May include a series of \fB::\fR namespace qualifiers +to specify a variable in a particular namespace. +.AP char *name2 in +If non-NULL, gives name of element within array and \fIname1\fR +must refer to an array variable. +.BE + +.SH DESCRIPTION +.PP +These procedures may be used to create, modify, read, and delete +Tcl variables from C code. +.PP +Note that \fBTcl_GetVar\fR and \fBTcl_SetVar\fR +have been largely replaced by the +object-based procedures \fBTcl_ObjGetVar2\fR and \fBTcl_ObjSetVar2\fR. +Those object-based procedures read, modify, and create +a variable whose name is held in a Tcl object instead of a string. +They also return a pointer to the object +which is the variable's value instead of returning a string. +Operations on objects can be faster since objects +hold an internal representation that can be manipulated more efficiently. +.PP +\fBTcl_SetVar\fR and \fBTcl_SetVar2\fR +will create a new variable or modify an existing one. +Both of these procedures set the given variable to the value +given by \fInewValue\fR, and they return a pointer to a +copy of the variable's new value, which is stored in Tcl's +variable structure. +Tcl keeps a private copy of the variable's value, so the caller +may change \fInewValue\fR after these procedures return without +affecting the value of the variable. +If an error occurs in setting the variable (e.g. an array +variable is referenced without giving an index into the array), +they return NULL. +.PP +The name of the variable may be specified to +\fBTcl_SetVar\fR and \fBTcl_SetVar2\fR in either of two ways. +If \fBTcl_SetVar\fR is called, the variable name is given as +a single string, \fIvarName\fR. +If \fIvarName\fR contains an open parenthesis and ends with a +close parenthesis, then the value between the parentheses is +treated as an index (which can have any string value) and +the characters before the first open +parenthesis are treated as the name of an array variable. +If \fIvarName\fR doesn't have parentheses as described above, then +the entire string is treated as the name of a scalar variable. +If \fBTcl_SetVar2\fR is called, then the array name and index +have been separated by the caller into two separate strings, +\fIname1\fR and \fIname2\fR respectively; if \fIname2\fR is +zero it means that a scalar variable is being referenced. +.PP +The \fIflags\fR argument may be used to specify any of several +options to the procedures. +It consists of an OR-ed combination of the following bits. +Note that the flag bit TCL_PARSE_PART1 is only meaningful +for the procedures Tcl_SetVar2 and Tcl_GetVar2. +.TP +\fBTCL_GLOBAL_ONLY\fR +Under normal circumstances the procedures look up variables as follows: +If a procedure call is active in \fIinterp\fR, +a variable is looked up at the current level of procedure call. +Otherwise, a variable is looked up first in the current namespace, +then in the global namespace. +However, if this bit is set in \fIflags\fR then the variable +is looked up only in the global namespace +even if there is a procedure call active. +If both \fBTCL_GLOBAL_ONLY\fR and \fBTCL_NAMESPACE_ONLY\fR are given, +\fBTCL_GLOBAL_ONLY\fR is ignored. +.TP +\fBTCL_NAMESPACE_ONLY\fR +Under normal circumstances the procedures look up variables as follows: +If a procedure call is active in \fIinterp\fR, +a variable is looked up at the current level of procedure call. +Otherwise, a variable is looked up first in the current namespace, +then in the global namespace. +However, if this bit is set in \fIflags\fR then the variable +is looked up only in the current namespace +even if there is a procedure call active. +.TP +\fBTCL_LEAVE_ERR_MSG\fR +If an error is returned and this bit is set in \fIflags\fR, then +an error message will be left in the interpreter's result, +where it can be retrieved with \fBTcl_GetObjResult\fR +or \fBTcl_GetStringResult\fR. +If this flag bit isn't set then no error message is left +and the interpreter's result will not be modified. +.TP +\fBTCL_APPEND_VALUE\fR +If this bit is set then \fInewValue\fR is appended to the current +value, instead of replacing it. +If the variable is currently undefined, then this bit is ignored. +.TP +\fBTCL_LIST_ELEMENT\fR +If this bit is set, then \fInewValue\fR is converted to a valid +Tcl list element before setting (or appending to) the variable. +A separator space is appended before the new list element unless +the list element is going to be the first element in a list or +sublist (i.e. the variable's current value is empty, or contains +the single character ``{'', or ends in `` }''). +.TP +\fBTCL_PARSE_PART1\fR +If this bit is set when calling \fITcl_SetVar2\fR and \fITcl_GetVar2\fR, +\fIname1\fR may contain both an array and an element name: +if the name contains an open parenthesis and ends with a +close parenthesis, then the value between the parentheses is +treated as an element name (which can have any string value) and +the characters before the first open +parenthesis are treated as the name of an array variable. +If the flag TCL_PARSE_PART1 is given, +\fIname2\fR should be NULL since the array and element names +are taken from \fIname1\fR. +.PP +\fBTcl_GetVar\fR and \fBTcl_GetVar2\fR +return the current value of a variable. +The arguments to these procedures are treated in the same way +as the arguments to \fBTcl_SetVar\fR and \fBTcl_SetVar2\fR. +Under normal circumstances, the return value is a pointer +to the variable's value (which is stored in Tcl's variable +structure and will not change before the next call to \fBTcl_SetVar\fR +or \fBTcl_SetVar2\fR). +\fBTcl_GetVar\fR and \fBTcl_GetVar2\fR use the flag bits TCL_GLOBAL_ONLY +and TCL_LEAVE_ERR_MSG, both of +which have +the same meaning as for \fBTcl_SetVar\fR. +In addition, \fBTcl_GetVar2\fR uses the bit TCL_PARSE_PART1, +which has the same meaning as for \fBTcl_SetVar2\fR. +If an error occurs in reading the variable (e.g. the variable +doesn't exist or an array element is specified for a scalar +variable), then NULL is returned. +.PP +\fBTcl_UnsetVar\fR and \fBTcl_UnsetVar2\fR may be used to remove +a variable, so that future calls to \fBTcl_GetVar\fR or \fBTcl_GetVar2\fR +for the variable will return an error. +The arguments to these procedures are treated in the same way +as the arguments to \fBTcl_GetVar\fR and \fBTcl_GetVar2\fR. +If the variable is successfully removed then TCL_OK is returned. +If the variable cannot be removed because it doesn't exist then +TCL_ERROR is returned. +If an array element is specified, the given element is removed +but the array remains. +If an array name is specified without an index, then the entire +array is removed. + +.SH "SEE ALSO" +Tcl_GetObjResult, Tcl_GetStringResult, Tcl_ObjGetVar2, Tcl_ObjSetVar2, Tcl_TraceVar + +.SH KEYWORDS +array, interpreter, object, scalar, set, unset, variable |