копировать строку фиксированной длины, возвращая указатель на конец массива (copy fixed length string, returning a pointer to the array end)
Пролог (Prolog)
This manual page is part of the POSIX Programmer's Manual. The
Linux implementation of this interface may differ (consult the
corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.
Имя (Name)
stpncpy, strncpy — copy fixed length string, returning a pointer
to the array end
Синопсис (Synopsis)
#include <string.h>
char *stpncpy(char *restrict s1, const char *restrict s2, size_t n);
char *strncpy(char *restrict s1, const char *restrict s2, size_t n);
Описание (Description)
For strncpy(): The functionality described on this reference page
is aligned with the ISO C standard. Any conflict between the
requirements described here and the ISO C standard is
unintentional. This volume of POSIX.1‐2017 defers to the ISO C
standard.
The stpncpy() and strncpy() functions shall copy not more than n
bytes (bytes that follow a NUL character are not copied) from the
array pointed to by s2 to the array pointed to by s1.
If the array pointed to by s2 is a string that is shorter than n
bytes, NUL characters shall be appended to the copy in the array
pointed to by s1, until n bytes in all are written.
If copying takes place between objects that overlap, the behavior
is undefined.
Возвращаемое значение (Return value)
If a NUL character is written to the destination, the stpncpy()
function shall return the address of the first such NUL
character. Otherwise, it shall return &s1[n].
The strncpy() function shall return s1.
No return values are reserved to indicate an error.
Ошибки (Error)
No errors are defined.
The following sections are informative.
Примеры (Examples)
None.
Использование в приложениях (Application usage)
Applications must provide the space in s1 for the n bytes to be
transferred, as well as ensure that the s2 and s1 arrays do not
overlap.
Character movement is performed differently in different
implementations. Thus, overlapping moves may yield surprises.
If there is no NUL character byte in the first n bytes of the
array pointed to by s2, the result is not null-terminated.
Обоснование (Rationale)
None.
Будущие направления (Future directions)
None.
Смотри также (See also)
strcpy(3p), wcsncpy(3p)
The Base Definitions volume of POSIX.1‐2017, string.h(0p)
