Merged into ISO C The functionality described on this page was merged into the mainline ISO C standard as of 6/2019, seestrdup(since C23)

Returns a pointer to a null-terminated byte string, which is a duplicateof the string pointed to bystr1. The returned pointer must be passed tofree to avoid a memory leak.

If an error occurs, a null pointer is returned anderrno may be set.

As all functions from Dynamic Memory TR,strdup is only guaranteed to be available if__STDC_ALLOC_LIB__ is defined by the implementation and if the user defines__STDC_WANT_LIB_EXT2__ to the integer constant1 before includingstring.h.

[edit]Parameters

[edit]Return value

A pointer to the newly allocated string, or a null pointer if an error occurred.

[edit]Notes

The function is identical to thePOSIX strdup.

[edit]Example

#ifdef __STDC_ALLOC_LIB__#define __STDC_WANT_LIB_EXT2__ 1#else#define _POSIX_C_SOURCE 200809L#endif #include <string.h>#include <assert.h>#include <stdlib.h> int main(void){constchar*s1="String";char*s2= strdup(s1);assert(strcmp(s1, s2)==0);free(s2);}

[edit]See also

• In other languages

• 日本語
• 中文