RTI Connext DDS Micro C++ API
Version 3.0.2
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String creation, cloning, assignment, and deletion. More...
Functions | |
char * | DDS_String_alloc (DDS_UnsignedLong 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. | |
RTI_INT32 | DDS_String_cmp (const char *s1, const char *s2) |
Compare two strings. | |
RTI_INT32 | DDS_String_ncmp (const char *s1, const char *s2, DDS_UnsignedLong num) |
Compare two strings. | |
RTI_INT32 | DDS_String_length (const char *string) |
Return the length of a string. |
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*'
.
The following conventions govern the memory management of strings in RTI Connext DDS Micro.
string
class methods. 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 DDS Micro must therefore make some assumptions when a user requests that a string be copied into. The following rules apply when RTI Connext DDS Micro is copying into a string or string sequence:
This requirement can generally be assured by adhering to the following idiom for manipulating strings.
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:
char* DDS_String_alloc | ( | DDS_UnsignedLong | 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.
length | <<in>> Capacity of the string. |
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()
str | <<in>> The string to duplicate. |
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.
string
must be either NULL, or must have been created using DDS_String_alloc(), DDS_String_dup()str | <<in>> The string to delete. |
RTI_INT32 DDS_String_cmp | ( | const char * | s1, |
const char * | s2 | ||
) |
RTI_INT32 DDS_String_ncmp | ( | const char * | s1, |
const char * | s2, | ||
DDS_UnsignedLong | num | ||
) |
Compare two strings.
This function compares two strings for lexicographic equivalence, but only up to num bytes.
[in] | s1 | <<in>> Left side of comparison |
[in] | s2 | <<in>> Right side of comparison |
[in] | num | Maximum number of bytes to compare |
RTI_INT32 DDS_String_length | ( | const char * | string | ) |
Return the length of a string.
string
must be non-NULLstring | <<in>> String to return length of |