String Support
[Infrastructure Module]

<<eXtension>> String creation, cloning, assignment, and deletion. More...

Functions

char * DDS_String_alloc (size_t length)
 Create a new empty string that can hold up to length characters.
char * DDS_String_dup (const char *str)
 Clone a string. Creates a new string that duplicates the value of string.
void DDS_String_free (char *str)
 Delete a string.
DDS_WcharDDS_Wstring_alloc (DDS_UnsignedLong length)
 Create a new empty string that can hold up to length wide characters.
DDS_UnsignedLong DDS_Wstring_length (const DDS_Wchar *str)
 Get the number of wide characters in the given string.
DDS_WcharDDS_Wstring_copy (DDS_Wchar *dst, const DDS_Wchar *src)
 Copy the source string over the destination string reallocating the space if it's necessary.
DDS_WcharDDS_Wstring_copy_and_widen (DDS_Wchar *dst, const char *src)
 Copy the source string over the destination string, widening each character.
DDS_WcharDDS_Wstring_dup (const DDS_Wchar *str)
 Clone a string of wide characters. Creates a new string that duplicates the value of string.
DDS_WcharDDS_Wstring_dup_and_widen (const char *str)
 Clone a string of characters as a string of wide characters.
void DDS_Wstring_free (DDS_Wchar *str)
 Delete a string.

Detailed Description

<<eXtension>> String creation, cloning, assignment, and deletion.

The methods in this class ensure consistent cross-platform implementations for string creation (DDS_String_alloc()), deletion (DDS_String_free()), and cloning (DDS_String_dup()) that preserve the mutable value type semantics. These are to be viewed as methods that define a string class whose data is represented by a 'char*'.

Conventions

The following conventions govern the memory management of strings in RTI Connext.

The representation of a string in C/C++ unfortunately does not allow programs to detect how much memory has been allocated for a string. RTI Connext must therefore make some assumptions when a user requests that a string be copied into. The following rules apply when RTI Connext is copying into a string or string sequence:

Usage

This requirement can generally be assured by adhering to the following idiom for manipulating strings.

     Always use 
          DDS_String_alloc() to create,
          DDS_String_dup() to clone,
          DDS_String_free() to delete
      a string 'char*' that is passed back and forth between 
      user code and the DDS C/C++ APIs.

Not adhering to this idiom can result in bad pointers, and incorrect memory being freed.

In addition, the user code should be vigilant to avoid memory leaks. It is good practice to:

See also:
DDS_StringSeq

Function Documentation

char* DDS_String_alloc ( size_t  length  ) 

Create a new empty string that can hold up to length characters.

A string created by this method must be deleted using DDS_String_free().

This function will allocate enough memory to hold a string of length characters, plus one additional byte to hold the NULL terminating character.

Parameters:
length <<in>> Capacity of the string.
Returns:
A newly created non-NULL string upon success or NULL upon failure.
Examples:
HelloWorld.cxx.

char* DDS_String_dup ( const char *  str  ) 

Clone a string. Creates a new string that duplicates the value of string.

A string created by this method must be deleted using DDS_String_free()

Parameters:
str <<in>> The string to duplicate.
Returns:
If string == NULL, this method always returns NULL. Otherwise, upon success it returns a newly created string whose value is string; upon failure it returns NULL.

void DDS_String_free ( char *  str  ) 

Delete a string.

Precondition:
string must be either NULL, or must have been created using DDS_String_alloc(), DDS_String_dup()
Parameters:
str <<in>> The string to delete.
Examples:
HelloWorld.cxx.

DDS_Wchar* DDS_Wstring_alloc ( DDS_UnsignedLong  length  ) 

Create a new empty string that can hold up to length wide characters.

A string created by this method must be deleted using DDS_Wstring_free()

This function will allocate enough memory to hold a string of length characters, plus one additional wide character to hold the NULL terminator.

Parameters:
length <<in>> Capacity of the string.
Returns:
A newly created non-NULL string upon success or NULL upon failure.

DDS_UnsignedLong DDS_Wstring_length ( const DDS_Wchar str  ) 

Get the number of wide characters in the given string.

The result does not count the terminating zero character.

Parameters:
str <<in>> A non-NULL string.
Returns:
The number of wide characters in the string.

DDS_Wchar* DDS_Wstring_copy ( DDS_Wchar dst,
const DDS_Wchar src 
)

Copy the source string over the destination string reallocating the space if it's necessary.

Parameters:
dst 
src 
Returns:
dst

DDS_Wchar* DDS_Wstring_copy_and_widen ( DDS_Wchar dst,
const char *  src 
)

Copy the source string over the destination string, widening each character.

Parameters:
dst <<in>> A non-NULL string to be overwritten by src.
src <<in>> A non-NULL string to be copied over dst
Returns:
dst

DDS_Wchar* DDS_Wstring_dup ( const DDS_Wchar str  ) 

Clone a string of wide characters. Creates a new string that duplicates the value of string.

A string created by this method must be deleted using DDS_Wstring_free().

Parameters:
str <<in>> The string to duplicate.
Returns:
If string == NULL, this method always returns NULL. Otherwise, upon success it returns a newly created string whose value is string; upon failure it returns NULL.

DDS_Wchar* DDS_Wstring_dup_and_widen ( const char *  str  ) 

Clone a string of characters as a string of wide characters.

A string created by this method must be deleted using DDS_Wstring_free()

Parameters:
str <<in>> The string to duplicate.
Returns:
If string == NULL, this method always returns NULL. Otherwise, upon success it returns a newly created string whose value is string; upon failure it returns NULL.

void DDS_Wstring_free ( DDS_Wchar str  ) 

Delete a string.

Precondition:
string must either NULL, or must have been created using DDS_Wstring_alloc(), DDS_Wstring_dup(), or DDS_Wstring_replace()
Parameters:
str <<in>> The string to delete.


RTI Connext C++ API Version 4.5f Copyright © 17 Mar 2012 Real-Time Innovations, Inc