stpncpy - Man Page

copy a fixed-size string, returning a pointer to its end


#include <string.h>

char *stpncpy(char *restrict dest, const char *restrict src, size_t n);

Feature Test Macro Requirements for glibc (see feature_test_macros(7)):


    Since glibc 2.10:
        _POSIX_C_SOURCE >= 200809L
    Before glibc 2.10:


The stpncpy() function copies at most n characters from the string pointed to by src, including the terminating null byte ('\0'), to the array pointed to by dest. Exactly n characters are written at dest. If the length strlen(src) is smaller than n, the remaining characters in the array pointed to by dest are filled with null bytes ('\0'), If the length strlen(src) is greater than or equal to n, the string pointed to by dest will not be null-terminated.

The strings may not overlap.

The programmer must ensure that there is room for at least n characters at dest.

Return Value

stpncpy() returns a pointer to the terminating null byte in dest, or, if dest is not null-terminated, dest+n.


For an explanation of the terms used in this section, see attributes(7).

stpncpy()Thread safetyMT-Safe

Conforming to

This function was added to POSIX.1-2008. Before that, it was a GNU extension. It first appeared in version 1.07 of the GNU C library in 1993.

See Also

strncpy(3), wcpncpy(3)


This page is part of release 5.13 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at

Referenced By

memstomp(1), signal-safety(7), stpcpy(3), strcpy(3), wcpncpy(3).

2021-03-22 GNU Linux Programmer's Manual