The strdup() and strndup() functions are used to duplicate a string.
strdup() :
Syntax : char *strdup(const char *s);
This function returns a pointer to a null-terminated byte string, which is a duplicate of the string pointed to by s. The memory obtained is done dynamically using malloc and hence it can be freed using free().
It returns a pointer to the duplicated string s.
Below is the C implementation to show the use of strdup() function in C:
// C program to demonstrate strdup() #include<stdio.h> #include<string.h> int main() { char source[] = "GeeksForGeeks"; // A copy of source is created dynamically // and pointer to copy is returned. char* target = strdup(source); printf("%s", target); return 0; } |
Output:
GeeksForGeeks
strndup() :
syntax: char *strndup(const char *s, size_t n);
This function is similar to strdup(), but copies at most n bytes.
Note: If s is longer than n, then only n bytes are copied, and a NULL (”) is added at the end.
Below is the C implementation to show the use of strndup() function in C:
// C program to demonstrate strndup() #include<stdio.h> #include<string.h> int main() { char source[] = "GeeksForGeeks"; // 5 bytes of source are copied to a new memory // allocated dynamically and pointer to copied // memory is returned. char* target = strndup(source, 5); printf("%s", target); return 0; } |
Output:
Geeks
Reference: Linux man(7)
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