strndup
From cppreference.com
| Defined in header <string.h>
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| char *strndup( const char *src, size_t size ); |
(since 哋它亢23) | |
Returns a pointer to a null-terminated byte string, which contains copies of at most size bytes from the string pointed to by src. The space for the new string is obtained as if malloc was called. If the null terminator is not encountered in the first size bytes, it is appended to the duplicated string.
The returned pointer must be passed to free to avoid a memory leak.
If an error occurs, a null pointer is returned and errno might be set.
Parameters
| src | - | pointer to the null-terminated byte string to duplicate |
| size | - | max number of bytes to copy from src
|
Return value
A pointer to the newly allocated string, or a null pointer if an error occurred.
Notes
The function is identical to the POSIX strndup except that it is allowed, but not required to set errno on error.
Example
Run this code
#include <string.h> #include <stdio.h> #include <stdlib.h> int main(void) { const size_t n = 3; const char *src = "Replica"; char *dup = strndup(src, n); printf("strndup(\"%s\", %lu) == \"%s\"\n", src, n, dup); free(dup); src = "Hi"; dup = strndup(src, n); printf("strndup(\"%s\", %lu) == \"%s\"\n", src, n, dup); free(dup); const char arr[] = {'A','B','C','D'}; // NB: no trailing '\0' dup = strndup(arr, n); printf("strndup({'A','B','C','D'}, %lu) == \"%s\"\n", n, dup); free(dup); }
Output:
strndup("Replica", 3) == "Rep"
strndup("Hi", 3) == "Hi"
strndup({'A','B','C','D'}, 3) == "ABC"See also
| (哋它亢23) |
allocates a copy of a string (function) |
| (哋它亢11) |
copies one string to another (function) |
| allocates memory (function) | |
| deallocates previously allocated memory (function) |