What does strdup mean in C?
to duplicate a string
The function strdup() is used to duplicate a string. It returns a pointer to null-terminated byte string. Here is the syntax of strdup() in C language, char *strdup(const char *string);
Can strdup fail?
The chance of strdup failing is determined by the chance of malloc failing. On modern operating systems with virtual memory, a malloc failure is a very rare thing. The OS may have even killed your entire process before the system gets so low on memory that malloc has to return NULL .
Does strdup need to be freed?
Because also strdup() allocates memory then it must be freed (see doc). strdup is a malloc in disguise. Reading the documentation of a standard function is faster than asking on SO ! strdup is not a Standard C function, however it is in POSIX.
Does strdup add null terminator?
The strdup() function allocates memory and copies into it the string addressed by s1, including the terminating null character.
Where is strdup defined?
strdup and strndup are defined in POSIX compliant systems as: char *strdup(const char *str); char *strndup(const char *str, size_t len); The strdup() function allocates sufficient memory for a copy of the string str , does the copy, and returns a pointer to it.
How is strdup implemented?
In the case of strdup, we use a specific function, malloc(), to allocate the memory dynamically. But it is favorable if you delete the content or free the space after usage. So for this purpose, simply use strdup() with malloc(), and then copy the source string to the allocated memory.
What does strdup return?
The strdup() function shall return a pointer to a new string on success. Otherwise, it shall return a null pointer and set errno to indicate the error. Upon successful completion, the strndup() function shall return a pointer to the newly allocated memory containing the duplicated string.
Does strdup allocate memory?
The strdup() function allocates sufficient memory for a copy of the string str , does the copy, and returns a pointer to it.
Why do we need strdup?
Use the strdup Function to Duplicate the Given String in C
It implements string copying functionality but does memory allocation and checking internally. Although a user is responsible for freeing the returned char pointer since the strdup allocates the memory with malloc function call.
Is strdup a standard?
Most C programmers are familiar with the strdup function. Many of them will take it for granted, yet it is not part of the C Standard (neither C89, C99 nor C11). It is part of POSIX and may not be available on all environments. Indeed Microsoft insisted on renaming it _strdup , adding to confusion.
Does strdup use malloc?
The strdup() function returns a pointer to a new string which is a duplicate of the string s. Memory for the new string is obtained with malloc(3), and can be freed with free(3).