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Diffstat (limited to 'doc/SetVar.3')
| -rw-r--r-- | doc/SetVar.3 | 235 |
1 files changed, 140 insertions, 95 deletions
diff --git a/doc/SetVar.3 b/doc/SetVar.3 index 32e7a4c..1bef20b 100644 --- a/doc/SetVar.3 +++ b/doc/SetVar.3 @@ -5,117 +5,173 @@ '\" 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 -'\" +.TH Tcl_SetVar 3 8.1 Tcl "Tcl Library Procedures" .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 +Tcl_SetVar2Ex, Tcl_SetVar, Tcl_SetVar2, Tcl_ObjSetVar2, Tcl_GetVar2Ex, Tcl_GetVar, Tcl_GetVar2, Tcl_ObjGetVar2, Tcl_UnsetVar, Tcl_UnsetVar2 \- manipulate Tcl variables .SH SYNOPSIS .nf \fB#include <tcl.h>\fR .sp -char * +Tcl_Obj * +\fBTcl_SetVar2Ex\fR(\fIinterp, name1, name2, newValuePtr, flags\fR) +.sp +const char * \fBTcl_SetVar\fR(\fIinterp, varName, newValue, flags\fR) .sp -char * +const char * \fBTcl_SetVar2\fR(\fIinterp, name1, name2, newValue, flags\fR) .sp -char * +Tcl_Obj * +\fBTcl_ObjSetVar2\fR(\fIinterp, part1Ptr, part2Ptr, newValuePtr, flags\fR) +.sp +Tcl_Obj * +\fBTcl_GetVar2Ex\fR(\fIinterp, name1, name2, flags\fR) +.sp +const char * \fBTcl_GetVar\fR(\fIinterp, varName, flags\fR) .sp -char * +const char * \fBTcl_GetVar2\fR(\fIinterp, name1, name2, flags\fR) .sp +Tcl_Obj * +\fBTcl_ObjGetVar2\fR(\fIinterp, part1Ptr, part2Ptr, 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 +.AS Tcl_Interp *newValuePtr .AP Tcl_Interp *interp in Interpreter containing variable. -.AP char *varName in +.AP "const char" *name1 in +Contains the name of an array variable (if \fIname2\fR is non-NULL) +or (if \fIname2\fR is NULL) either the name of a scalar variable +or a complete name including both variable name and index. +May include \fB::\fR namespace qualifiers +to specify a variable in a particular namespace. +.AP "const char" *name2 in +If non-NULL, gives name of element within array; in this +case \fIname1\fR must refer to an array variable. +.AP Tcl_Obj *newValuePtr in +Points to a Tcl value containing the new value for the variable. +.AP int flags in +OR-ed combination of bits providing additional information. See below +for valid values. +.AP "const char" *varName in Name of variable. -May include a series of \fB::\fR namespace qualifiers +May include \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 +an array. +.AP "const char" *newValue in +New value for variable, specified as a null-terminated string. +A copy of this value is stored in the variable. +.AP Tcl_Obj *part1Ptr in +Points to a Tcl value containing the variable's name. +The name 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. +May refer to a scalar variable or an element of an array variable. +.AP Tcl_Obj *part2Ptr in +If non-NULL, points to a value containing the name of an element +within an array and \fIpart1Ptr\fR must refer to an array variable. .BE .SH DESCRIPTION .PP -These procedures may be used to create, modify, read, and delete +These procedures are 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 +\fBTcl_SetVar2Ex\fR, \fBTcl_SetVar\fR, \fBTcl_SetVar2\fR, and +\fBTcl_ObjSetVar2\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 +These procedures set the given variable to the value +given by \fInewValuePtr\fR or \fInewValue\fR and return a +pointer to 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. +\fBTcl_SetVar2Ex\fR and \fBTcl_ObjSetVar2\fR take the new value as a +Tcl_Obj and return +a pointer to a Tcl_Obj. \fBTcl_SetVar\fR and \fBTcl_SetVar2\fR +take the new value as a string and return a string; they are +usually less efficient than \fBTcl_ObjSetVar2\fR. Note that the +return value may be different than the \fInewValuePtr\fR or +\fInewValue\fR 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), -they return NULL. +variable is referenced without giving an index into the array) +NULL is returned and an error message is left in \fIinterp\fR's +result if the \fBTCL_LEAVE_ERR_MSG\fR \fIflag\fR bit is set. +.PP +\fBTcl_GetVar2Ex\fR, \fBTcl_GetVar\fR, \fBTcl_GetVar2\fR, and +\fBTcl_ObjGetVar2\fR +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 \fBTcl_GetVar2Ex\fR and +\fBTcl_ObjGetVar2\fR the value is +returned as a pointer to a Tcl_Obj. For \fBTcl_GetVar\fR and +\fBTcl_GetVar2\fR the value is returned as a string; this is +usually less efficient, so \fBTcl_GetVar2Ex\fR or \fBTcl_ObjGetVar2\fR +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 \fIinterp\fR's result if the \fBTCL_LEAVE_ERR_MSG\fR \fIflag\fR +bit is set. +.PP +\fBTcl_UnsetVar\fR and \fBTcl_UnsetVar2\fR 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 \fBTCL_OK\fR is returned. +If the variable cannot be removed because it does not exist then +\fBTCL_ERROR\fR is returned and an error message is left +in \fIinterp\fR's result if the \fBTCL_LEAVE_ERR_MSG\fR \fIflag\fR +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. .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 +The name of a variable may be specified to these procedures in +four ways: +.IP [1] +If \fBTcl_SetVar\fR, \fBTcl_GetVar\fR, or \fBTcl_UnsetVar\fR +is invoked, 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 +If \fIvarName\fR does not 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. +.IP [2] +If the \fIname1\fR and \fIname2\fR arguments are provided and +\fIname2\fR is non-NULL, then an array element is specified and +the array name and index have +already been separated by the caller: \fIname1\fR contains the +name and \fIname2\fR contains the index. An error is generated +if \fIname1\fR contains an open parenthesis and ends with a +close parenthesis (array element) and \fIname2\fR is non-NULL. +.IP [3] +If \fIname2\fR is NULL, \fIname1\fR is treated just like +\fIvarName\fR in case [1] above (it can be either a scalar or an array +element variable name). .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: +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, +the variable is looked up at the current level of procedure call. +Otherwise, the 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 @@ -124,27 +180,24 @@ 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. +If this bit is set in \fIflags\fR then the variable +is looked up only in the current namespace; if a procedure is active +its variables are ignored, and the global namespace is also ignored unless +it is the current namespace. .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 +If this flag bit is not 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. +If this bit is set then \fInewValuePtr\fR or \fInewValue\fR is +appended to the current value instead of replacing it. +If the variable is currently undefined, then the bit is ignored. +This bit is only used by the \fBTcl_Set*\fR procedures. .TP \fBTCL_LIST_ELEMENT\fR If this bit is set, then \fInewValue\fR is converted to a valid @@ -152,19 +205,13 @@ 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. +the single character +.QW { , +or ends in +.QW " }" ). +When appending, the original value of the variable must also be +a valid list, so that the operation is the appending of a new +list element onto a list. .PP \fBTcl_GetVar\fR and \fBTcl_GetVar2\fR return the current value of a variable. @@ -174,14 +221,12 @@ 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 +\fBTcl_GetVar\fR and \fBTcl_GetVar2\fR use the flag bits \fBTCL_GLOBAL_ONLY\fR +and \fBTCL_LEAVE_ERR_MSG\fR, 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 +does not 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 @@ -189,16 +234,16 @@ 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 the variable is successfully removed then \fBTCL_OK\fR is returned. +If the variable cannot be removed because it does not exist then +\fBTCL_ERROR\fR 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 +Tcl_GetObjResult, Tcl_GetStringResult, Tcl_TraceVar .SH KEYWORDS -array, interpreter, object, scalar, set, unset, variable +array, get variable, interpreter, scalar, set, unset, value, variable |