Documentation generated from fossil trunk
Tcl_SetVar2Ex, Tcl_SetVar, Tcl_SetVar2, Tcl_ObjSetVar2, Tcl_GetVar2Ex, Tcl_GetVar, Tcl_GetVar2, Tcl_ObjGetVar2, Tcl_UnsetVar, Tcl_UnsetVar2 -
manipulate Tcl variables
#include <tcl.h> Tcl_Obj * Tcl_SetVar2Ex(interp, name1, name2, newValuePtr, flags) const char * Tcl_SetVar(interp, varName, newValue, flags) const char * Tcl_SetVar2(interp, name1, name2, newValue, flags) Tcl_Obj * Tcl_ObjSetVar2(interp, part1Ptr, part2Ptr, newValuePtr, flags) Tcl_Obj * Tcl_GetVar2Ex(interp, name1, name2, flags) const char * Tcl_GetVar(interp, varName, flags) const char * Tcl_GetVar2(interp, name1, name2, flags) Tcl_Obj * Tcl_ObjGetVar2(interp, part1Ptr, part2Ptr, flags) int Tcl_UnsetVar(interp, varName, flags) int Tcl_UnsetVar2(interp, name1, name2, flags)
Type | Name | Mode |
---|---|---|
Tcl_Interp | *interp | in |
Interpreter containing variable. | ||
const char | *name1 | in |
Contains the name of an array variable (if name2 is non-NULL) or (if name2 is NULL) either the name of a scalar variable or a complete name including both variable name and index. May include :: namespace qualifiers to specify a variable in a particular namespace. | ||
const char | *name2 | in |
If non-NULL, gives name of element within array; in this case name1 must refer to an array variable. | ||
Tcl_Obj | *newValuePtr | in |
Points to a Tcl value containing the new value for the variable. | ||
int | flags | in |
OR-ed combination of bits providing additional information. See below for valid values. | ||
const char | *varName | in |
Name of variable. May include :: namespace qualifiers to specify a variable in a particular namespace. May refer to a scalar variable or an element of an array. | ||
const char | *newValue | in |
New value for variable, specified as a null-terminated string. A copy of this value is stored in the variable. | ||
Tcl_Obj | *part1Ptr | in |
Points to a Tcl value containing the variable's name. The name may include a series of :: namespace qualifiers to specify a variable in a particular namespace. May refer to a scalar variable or an element of an array variable. | ||
Tcl_Obj | *part2Ptr | in |
If non-NULL, points to a value containing the name of an element within an array and part1Ptr must refer to an array variable. |
These procedures are used to create, modify, read, and delete Tcl variables from C code.
Tcl_SetVar2Ex, Tcl_SetVar, Tcl_SetVar2, and Tcl_ObjSetVar2 will create a new variable or modify an existing one. These procedures set the given variable to the value given by newValuePtr or newValue and return a pointer to the variable's new value, which is stored in Tcl's variable structure. Tcl_SetVar2Ex and Tcl_ObjSetVar2 take the new value as a Tcl_Obj and return a pointer to a Tcl_Obj. Tcl_SetVar and Tcl_SetVar2 take the new value as a string and return a string; they are usually less efficient than Tcl_ObjSetVar2. Note that the return value may be different than the newValuePtr or newValue argument, due to modifications made by write traces. If an error occurs in setting the variable (e.g. an array variable is referenced without giving an index into the array) NULL is returned and an error message is left in interp's result if the TCL_LEAVE_ERR_MSG flag bit is set.
Tcl_GetVar2Ex, Tcl_GetVar, Tcl_GetVar2, and Tcl_ObjGetVar2 return the current value of a variable. The arguments to these procedures are treated in the same way as the arguments to the procedures described above. Under normal circumstances, the return value is a pointer to the variable's value. For Tcl_GetVar2Ex and Tcl_ObjGetVar2 the value is returned as a pointer to a Tcl_Obj. For Tcl_GetVar and Tcl_GetVar2 the value is returned as a string; this is usually less efficient, so Tcl_GetVar2Ex or Tcl_ObjGetVar2 are preferred. If an error occurs while reading the variable (e.g. the variable does not exist or an array element is specified for a scalar variable), then NULL is returned and an error message is left in interp's result if the TCL_LEAVE_ERR_MSG flag bit is set.
Tcl_UnsetVar and Tcl_UnsetVar2 may be used to remove a variable, so that future attempts to read the variable will return an error. The arguments to these procedures are treated in the same way as the arguments to the procedures above. If the variable is successfully removed then TCL_OK is returned. If the variable cannot be removed because it does not exist then TCL_ERROR is returned and an error message is left in interp's result if the TCL_LEAVE_ERR_MSG flag bit is set. 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.
The name of a variable may be specified to these procedures in four ways:
The flags argument may be used to specify any of several options to the procedures. It consists of an OR-ed combination of the following bits.
Tcl_GetVar and Tcl_GetVar2 return the current value of a variable. The arguments to these procedures are treated in the same way as the arguments to Tcl_SetVar and Tcl_SetVar2. 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 Tcl_SetVar or Tcl_SetVar2). Tcl_GetVar and Tcl_GetVar2 use the flag bits TCL_GLOBAL_ONLY and TCL_LEAVE_ERR_MSG, both of which have the same meaning as for Tcl_SetVar. If an error occurs in reading the variable (e.g. the variable does not exist or an array element is specified for a scalar variable), then NULL is returned.
Tcl_UnsetVar and Tcl_UnsetVar2 may be used to remove a variable, so that future calls to Tcl_GetVar or Tcl_GetVar2 for the variable will return an error. The arguments to these procedures are treated in the same way as the arguments to Tcl_GetVar and Tcl_GetVar2. If the variable is successfully removed then TCL_OK is returned. If the variable cannot be removed because it does not 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.
Tcl_GetObjResult, Tcl_GetStringResult, Tcl_TraceVar
array, get variable, interpreter, scalar, set, unset, value, variable