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StringPtr
Str255 data type
#include <Types.h>
typedef unsigned char Str255[256] ; address of 256 unsigned bytes
Variations of the Str255 types are available in different lengths. These are
typedef unsigned char Str63[64];
typedef unsigned char Str32[33];
typedef unsigned char Str31[32];
typedef unsigned char Str27[28];
typedef unsigned char Str15[16];
typedef const unsigned char *ConstStr255Param; address of constant unsigned
byte. Used primarily as a
parameter type in function
declarations
Variations of the ConstStr255Param type are available in different lengths. These are
typedef unsigned char *ConstStr63Param;
typedef unsigned char *ConstStr32Param;
typedef unsigned char *ConstStr31Param;
typedef unsigned char *ConstStr27Param;
typedef unsigned char *ConstStr15Param;
typedef unsigned char * StringPtr; address of an unsigned byte
typedef unsigned char ** StringHandle; handle leading to an unsigned byte
Notes: Str255 is the C-structure name for a length-prefixed Pascal- style
string. The first byte of an Str255 is assumed to be the length of the text
and the following bytes (up to 255 of them) are considered the text of the
string.
The following functions are directly related to the use of Str255s:
DrawString IUCompString NumToString StringToNum
EqualString IUEqualString RelString StringWidth
GetIndString NewString SetString UprString
These functions also use a Str255 as a required parameter:
AppendMenu GetFNum OpenDriver SetFLock
Create GetFontName OpenResFile SetIText
CreateResFile GetNamedResource OpenRF SetWTitle
DIZero GetWTitle OpenRFPerm SFGetFile
FSDelete InsMenuItem ParamText SFPGetFile
FSOpen NewDialog Rename SFPPutFile
Get1NamedResource NewMenu RstFLock SFPutFile
GetCTitle NewWindow SetCTitle StuffHex
GetFInfo OpenDeskAcc SetFInfo
The Str255 data type uses up 256 bytes of storage. Note that this is
inefficient in many cases. For instance, even though FSOpen wants an
Str255, filenames are never larger than 64 bytes (length + 63
characters). An array of filenames declared as either of:
Str255 nameArray[20]; /* takes 5120 bytes of storage */
Str63 nameArray[20]; /* takes only 1280 bytes */
The latter is clearly preferable ... and FSOpen( nameArray[j],...) works
perfectly well either way.
Note that if a toolbox call returns Str255 as a variable parameter (eg,
GetWTitle), you better be sure that the pointer you pass really points to
fully 256 bytes of available storage!
In some cases is it more convenient to use ASCIIZ strings and call standard
C library functions such as strlen, strcpy, and so forth.
Referenced by (163):