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Diffstat (limited to 'doc/StringObj.3')
| -rw-r--r-- | doc/StringObj.3 | 154 |
1 files changed, 81 insertions, 73 deletions
diff --git a/doc/StringObj.3 b/doc/StringObj.3 index e451c61..e6f9d32 100644 --- a/doc/StringObj.3 +++ b/doc/StringObj.3 @@ -8,7 +8,7 @@ .TH Tcl_StringObj 3 8.1 Tcl "Tcl Library Procedures" .BS .SH NAME -Tcl_NewStringObj, Tcl_NewUnicodeObj, Tcl_SetStringObj, Tcl_SetUnicodeObj, Tcl_GetStringFromObj, Tcl_GetString, Tcl_GetUnicodeFromObj, Tcl_GetUnicode, Tcl_GetUniChar, Tcl_GetCharLength, Tcl_GetRange, Tcl_AppendToObj, Tcl_AppendUnicodeToObj, Tcl_AppendObjToObj, Tcl_AppendStringsToObj, Tcl_AppendStringsToObjVA, Tcl_AppendLimitedToObj, Tcl_Format, Tcl_AppendFormatToObj, Tcl_ObjPrintf, Tcl_AppendPrintfToObj, Tcl_SetObjLength, Tcl_AttemptSetObjLength, Tcl_ConcatObj \- manipulate Tcl objects as strings +Tcl_NewStringObj, Tcl_NewUnicodeObj, Tcl_SetStringObj, Tcl_SetUnicodeObj, Tcl_GetStringFromObj, Tcl_GetString, Tcl_GetUnicodeFromObj, Tcl_GetUnicode, Tcl_GetUniChar, Tcl_GetCharLength, Tcl_GetRange, Tcl_AppendToObj, Tcl_AppendUnicodeToObj, Tcl_AppendObjToObj, Tcl_AppendStringsToObj, Tcl_AppendStringsToObjVA, Tcl_AppendLimitedToObj, Tcl_Format, Tcl_AppendFormatToObj, Tcl_ObjPrintf, Tcl_AppendPrintfToObj, Tcl_SetObjLength, Tcl_AttemptSetObjLength, Tcl_ConcatObj \- manipulate Tcl values as strings .SH SYNOPSIS .nf \fB#include <tcl.h>\fR @@ -60,7 +60,6 @@ void .sp void \fBTcl_AppendStringsToObjVA\fR(\fIobjPtr, argList\fR) -.VS 8.5 .sp void \fBTcl_AppendLimitedToObj\fR(\fIobjPtr, bytes, length, limit, ellipsis\fR) @@ -74,9 +73,8 @@ int Tcl_Obj * \fBTcl_ObjPrintf\fR(\fIformat, ...\fR) .sp -int +void \fBTcl_AppendPrintfToObj\fR(\fIobjPtr, format, ...\fR) -.VE 8.5 .sp void \fBTcl_SetObjLength\fR(\fIobjPtr, newLength\fR) @@ -90,7 +88,7 @@ Tcl_Obj * .AS "const Tcl_UniChar" *appendObjPtr in/out .AP "const char" *bytes in Points to the first byte of an array of UTF-8-encoded bytes -used to set or append to a string object. +used to set or append to a string value. This byte array may contain embedded null characters unless \fInumChars\fR is negative. (Applications needing null bytes should represent them as the two-byte sequence \fI\e700\e600\fR, use @@ -98,88 +96,89 @@ should represent them as the two-byte sequence \fI\e700\e600\fR, use the string is a collection of uninterpreted bytes.) .AP int length in The number of bytes to copy from \fIbytes\fR when -initializing, setting, or appending to a string object. +initializing, setting, or appending to a string value. If negative, all bytes up to the first null are used. .AP "const Tcl_UniChar" *unicode in Points to the first byte of an array of Unicode characters -used to set or append to a string object. +used to set or append to a string value. This byte array may contain embedded null characters unless \fInumChars\fR is negative. .AP int numChars in The number of Unicode characters to copy from \fIunicode\fR when -initializing, setting, or appending to a string object. +initializing, setting, or appending to a string value. If negative, all characters up to the first null character are used. .AP int index in The index of the Unicode character to return. .AP int first in The index of the first Unicode character in the Unicode range to be -returned as a new object. +returned as a new value. .AP int last in The index of the last Unicode character in the Unicode range to be -returned as a new object. +returned as a new value. .AP Tcl_Obj *objPtr in/out -Points to an object to manipulate. +Points to a value to manipulate. .AP Tcl_Obj *appendObjPtr in -The object to append to \fIobjPtr\fR in \fBTcl_AppendObjToObj\fR. +The value to append to \fIobjPtr\fR in \fBTcl_AppendObjToObj\fR. .AP int *lengthPtr out If non-NULL, the location where \fBTcl_GetStringFromObj\fR will store -the length of an object's string representation. +the length of a value's string representation. .AP "const char" *string in Null-terminated string value to append to \fIobjPtr\fR. .AP va_list argList in -An argument list which must have been initialised using +An argument list which must have been initialized using \fBva_start\fR, and cleared using \fBva_end\fR. .AP int limit in Maximum number of bytes to be appended. .AP "const char" *ellipsis in Suffix to append when the limit leads to string truncation. -If NULL is passed then the suffix "..." is used. +If NULL is passed then the suffix +.QW "..." +is used. .AP "const char" *format in Format control string including % conversion specifiers. .AP int objc in The number of elements to format or concatenate. .AP Tcl_Obj *objv[] in -The array of objects to format or concatenate. +The array of values to format or concatenate. .AP int newLength in New length for the string value of \fIobjPtr\fR, not including the final null character. .BE - .SH DESCRIPTION .PP -The procedures described in this manual entry allow Tcl objects to +The procedures described in this manual entry allow Tcl values to be manipulated as string values. They use the internal representation -of the object to store additional information to make the string +of the value to store additional information to make the string manipulations more efficient. In particular, they make a series of append operations efficient by allocating extra storage space for the string so that it does not have to be copied for each append. Also, indexing and length computations are optimized because the Unicode string representation is calculated and cached as needed. When using the \fBTcl_Append*\fR family of functions where the -interpreter's result is the object being appended to, it is important +interpreter's result is the value being appended to, it is important to call Tcl_ResetResult first to ensure you are not unintentionally -appending to existing data in the result object. +appending to existing data in the result value. .PP -\fBTcl_NewStringObj\fR and \fBTcl_SetStringObj\fR create a new object -or modify an existing object to hold a copy of the string given by +\fBTcl_NewStringObj\fR and \fBTcl_SetStringObj\fR create a new value +or modify an existing value to hold a copy of the string given by \fIbytes\fR and \fIlength\fR. \fBTcl_NewUnicodeObj\fR and -\fBTcl_SetUnicodeObj\fR create a new object or modify an existing -object to hold a copy of the Unicode string given by \fIunicode\fR and +\fBTcl_SetUnicodeObj\fR create a new value or modify an existing +value to hold a copy of the Unicode string given by \fIunicode\fR and \fInumChars\fR. \fBTcl_NewStringObj\fR and \fBTcl_NewUnicodeObj\fR -return a pointer to a newly created object with reference count zero. -All four procedures set the object to hold a copy of the specified +return a pointer to a newly created value with reference count zero. +All four procedures set the value to hold a copy of the specified string. \fBTcl_SetStringObj\fR and \fBTcl_SetUnicodeObj\fR free any old string representation as well as any old internal representation -of the object. +of the value. .PP -\fBTcl_GetStringFromObj\fR and \fBTcl_GetString\fR return an object's +\fBTcl_GetStringFromObj\fR and \fBTcl_GetString\fR return a value's string representation. This is given by the returned byte pointer and (for \fBTcl_GetStringFromObj\fR) length, which is stored in -\fIlengthPtr\fR if it is non-NULL. If the object's UTF string +\fIlengthPtr\fR if it is non-NULL. If the value's UTF string representation is invalid (its byte pointer is NULL), the string -representation is regenerated from the object's internal +representation is regenerated from the value's internal representation. The storage referenced by the returned byte pointer -is owned by the object manager. It is passed back as a writable +is owned by the value manager. It is passed back as a writable pointer so that extension author creating their own \fBTcl_ObjType\fR will be able to modify the string representation within the \fBTcl_UpdateStringProc\fR of their \fBTcl_ObjType\fR. Except for that @@ -195,45 +194,45 @@ The procedure \fBTcl_GetString\fR is used in the common case where the caller does not need the length of the string representation. .PP -\fBTcl_GetUnicodeFromObj\fR and \fBTcl_GetUnicode\fR return an object's +\fBTcl_GetUnicodeFromObj\fR and \fBTcl_GetUnicode\fR return a value's value as a Unicode string. This is given by the returned pointer and (for \fBTcl_GetUnicodeFromObj\fR) length, which is stored in \fIlengthPtr\fR if it is non-NULL. The storage referenced by the returned -byte pointer is owned by the object manager and should not be modified by +byte pointer is owned by the value manager and should not be modified by the caller. The procedure \fBTcl_GetUnicode\fR is used in the common case where the caller does not need the length of the unicode string representation. .PP \fBTcl_GetUniChar\fR returns the \fIindex\fR'th character in the -object's Unicode representation. +value's Unicode representation. .PP -\fBTcl_GetRange\fR returns a newly created object comprised of the +\fBTcl_GetRange\fR returns a newly created value comprised of the characters between \fIfirst\fR and \fIlast\fR (inclusive) in the -object's Unicode representation. If the object's Unicode +value's Unicode representation. If the value's Unicode representation is invalid, the Unicode representation is regenerated -from the object's string representation. +from the value's string representation. .PP \fBTcl_GetCharLength\fR returns the number of characters (as opposed -to bytes) in the string object. +to bytes) in the string value. .PP \fBTcl_AppendToObj\fR appends the data given by \fIbytes\fR and -\fIlength\fR to the string representation of the object specified by -\fIobjPtr\fR. If the object has an invalid string representation, +\fIlength\fR to the string representation of the value specified by +\fIobjPtr\fR. If the value has an invalid string representation, then an attempt is made to convert \fIbytes\fR is to the Unicode format. If the conversion is successful, then the converted form of -\fIbytes\fR is appended to the object's Unicode representation. -Otherwise, the object's Unicode representation is invalidated and +\fIbytes\fR is appended to the value's Unicode representation. +Otherwise, the value's Unicode representation is invalidated and converted to the UTF format, and \fIbytes\fR is appended to the -object's new string representation. +value's new string representation. .PP \fBTcl_AppendUnicodeToObj\fR appends the Unicode string given by -\fIunicode\fR and \fInumChars\fR to the object specified by -\fIobjPtr\fR. If the object has an invalid Unicode representation, +\fIunicode\fR and \fInumChars\fR to the value specified by +\fIobjPtr\fR. If the value has an invalid Unicode representation, then \fIunicode\fR is converted to the UTF format and appended to the -object's string representation. Appends are optimized to handle -repeated appends relatively efficiently (it overallocates the string +value's string representation. Appends are optimized to handle +repeated appends relatively efficiently (it over-allocates the string or Unicode space to avoid repeated reallocations and copies of -object's string value). +value's string value). .PP \fBTcl_AppendObjToObj\fR is similar to \fBTcl_AppendToObj\fR, but it appends the string or Unicode value (whichever exists and is best @@ -251,7 +250,6 @@ must be a NULL pointer to indicate the end of the list. except that instead of taking a variable number of arguments it takes an argument list. .PP -.VS 8.5 \fBTcl_AppendLimitedToObj\fR is similar to \fBTcl_AppendToObj\fR except that it imposes a limit on how many bytes are appended. This can be handy when the string to be appended might be @@ -275,9 +273,11 @@ bytes is necessary to append only whole multi-byte characters. \fBTcl_Format\fR is the C-level interface to the engine of the \fBformat\fR command. The actual command procedure for \fBformat\fR is little more than +.PP .CS -Tcl_Format(interp, Tcl_GetString(objv[1]), objc-2, objv+2); +\fBTcl_Format\fR(interp, \fBTcl_GetString\fR(objv[1]), objc-2, objv+2); .CE +.PP The \fIobjc\fR Tcl_Obj values in \fIobjv\fR are formatted into a string according to the conversion specification in \fIformat\fR argument, following the documentation for the \fBformat\fR command. The resulting formatted @@ -287,22 +287,26 @@ returned, and an error message is recorded in \fIinterp\fR, if \fIinterp\fR is non-NULL. .PP \fBTcl_AppendFormatToObj\fR is an appending alternative form -of \fBTcl_Format\fR with functionality equivalent to +of \fBTcl_Format\fR with functionality equivalent to: +.PP .CS -Tcl_Obj *newPtr = Tcl_Format(interp, format, objc, objv); +Tcl_Obj *newPtr = \fBTcl_Format\fR(interp, format, objc, objv); if (newPtr == NULL) return TCL_ERROR; -Tcl_AppendObjToObj(objPtr, newPtr); +\fBTcl_AppendObjToObj\fR(objPtr, newPtr); return TCL_OK; .CE +.PP but with greater convenience and efficiency when the appending functionality is needed. .PP \fBTcl_ObjPrintf\fR serves as a replacement for the common sequence +.PP .CS char buf[SOME_SUITABLE_LENGTH]; sprintf(buf, format, ...); -Tcl_NewStringObj(buf, -1); +\fBTcl_NewStringObj\fR(buf, -1); .CE +.PP but with greater convenience and no need to determine \fBSOME_SUITABLE_LENGTH\fR. The formatting is done with the same core formatting engine used by \fBTcl_Format\fR. This means the set of @@ -315,34 +319,40 @@ assumption that C code is more likely to know how many bytes it is passing around than the number of encoded characters those bytes happen to represent. The variable number of arguments passed in should be of the types that would be suitable for passing to \fBsprintf\fR. Note in -this example usage, \fIx\fR is of type \fBlong\fR. +this example usage, \fIx\fR is of type \fBint\fR. +.PP .CS -long x = 5; -Tcl_Obj *objPtr = Tcl_ObjPrintf("Value is %d", x); +int x = 5; +Tcl_Obj *objPtr = \fBTcl_ObjPrintf\fR("Value is %d", x); .CE +.PP If the value of \fIformat\fR contains internal inconsistencies or invalid specifier formats, the formatted string result produced by -\fBTcl_ObjPrintf\fR will be an error message describing the error. +\fBTcl_ObjPrintf\fR will be an error message describing the error. +It is impossible however to provide runtime protection against +mismatches between the format and any subsequent arguments. +Compile-time protection may be provided by some compilers. .PP \fBTcl_AppendPrintfToObj\fR is an appending alternative form of \fBTcl_ObjPrintf\fR with functionality equivalent to +.PP .CS -Tcl_AppendObjToObj(objPtr, Tcl_ObjPrintf(format, ...)); +\fBTcl_AppendObjToObj\fR(objPtr, \fBTcl_ObjPrintf\fR(format, ...)); .CE +.PP but with greater convenience and efficiency when the appending functionality is needed. -.VE 8.5 .PP The \fBTcl_SetObjLength\fR procedure changes the length of the string value of its \fIobjPtr\fR argument. If the \fInewLength\fR -argument is greater than the space allocated for the object's +argument is greater than the space allocated for the value's string, then the string space is reallocated and the old value is copied to the new space; the bytes between the old length of the string and the new length may have arbitrary values. If the \fInewLength\fR argument is less than the current length -of the object's string, with \fIobjPtr->length\fR is reduced without +of the value's string, with \fIobjPtr->length\fR is reduced without reallocating the string space; the original allocated size for the -string is recorded in the object, so that the string length can be +string is recorded in the value, so that the string length can be enlarged in a subsequent call to \fBTcl_SetObjLength\fR without reallocating storage. In all cases \fBTcl_SetObjLength\fR leaves a null character at \fIobjPtr->bytes[newLength]\fR. @@ -351,26 +361,24 @@ a null character at \fIobjPtr->bytes[newLength]\fR. \fBTcl_SetObjLength\fR except that if sufficient memory to satisfy the request cannot be allocated, it does not cause the Tcl interpreter to \fBpanic\fR. Thus, if \fInewLength\fR is greater than the space -allocated for the object's string, and there is not enough memory +allocated for the value's string, and there is not enough memory available to satisfy the request, \fBTcl_AttemptSetObjLength\fR will take no action and return 0 to indicate failure. If there is enough memory to satisfy the request, \fBTcl_AttemptSetObjLength\fR behaves just like \fBTcl_SetObjLength\fR and returns 1 to indicate success. .PP -The \fBTcl_ConcatObj\fR function returns a new string object whose +The \fBTcl_ConcatObj\fR function returns a new string value whose value is the space-separated concatenation of the string -representations of all of the objects in the \fIobjv\fR +representations of all of the values in the \fIobjv\fR array. \fBTcl_ConcatObj\fR eliminates leading and trailing white space as it copies the string representations of the \fIobjv\fR array to the result. If an element of the \fIobjv\fR array consists of nothing but -white space, then that object is ignored entirely. This white-space +white space, then that value is ignored entirely. This white-space removal was added to make the output of the \fBconcat\fR command cleaner-looking. \fBTcl_ConcatObj\fR returns a pointer to a -newly-created object whose ref count is zero. - +newly-created value whose ref count is zero. .SH "SEE ALSO" -Tcl_NewObj, Tcl_IncrRefCount, Tcl_DecrRefCount, format, sprintf - +Tcl_NewObj(3), Tcl_IncrRefCount(3), Tcl_DecrRefCount(3), format(n), sprintf(3) .SH KEYWORDS -append, internal representation, object, object type, string object, +append, internal representation, value, value type, string value, string type, string representation, concat, concatenate, unicode |