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| Character manipulation | |||||||||||||||||||||||||||||||||||||||||
| Conversions to and from numeric formats | |||||||||||||||||||||||||||||||||||||||||
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| String manipulation | |||||||||||||||||||||||||||||||||||||||||
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| String examination | |||||||||||||||||||||||||||||||||||||||||
| Memory manipulation | |||||||||||||||||||||||||||||||||||||||||
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| Miscellaneous | |||||||||||||||||||||||||||||||||||||||||
(C11)(C11) | |||||||||||||||||||||||||||||||||||||||||
Defined in header <string.h> | ||
char*strndup(constchar*src,size_t size); | (since C23) | |
Returns a pointer to a null-terminated byte string, which contains copies of at mostsize bytes from the string pointed to bysrc. The space for the new string is obtained as ifmalloc was called. If the null terminator is not encountered in the firstsize bytes, it is appended to the duplicated string.
The returned pointer must be passed tofree to avoid a memory leak.
If an error occurs, a null pointer is returned anderrno might be set.
Contents |
| src | - | pointer to the null-terminated byte string to duplicate |
| size | - | max number of bytes to copy fromsrc |
A pointer to the newly allocated string, or a null pointer if an error occurred.
The function is identical to thePOSIX strndup except that it is allowed, but not required to seterrno on error.
#include <string.h>#include <stdio.h>#include <stdlib.h> int main(void){constsize_t n=3; constchar*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); constchar 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"(C23) | allocates a copy of a string (function)[edit] |
(C11) | copies one string to another (function)[edit] |
| allocates memory (function)[edit] | |
| deallocates previously allocated memory (function)[edit] |
