получить длину строки фиксированного размера (get length of fixed size string)
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)
strlen, strnlen — get length of fixed size string
Синопсис (Synopsis)
#include <string.h>
size_t strlen(const char *s);
size_t strnlen(const char *s, size_t maxlen);
Описание (Description)
For strlen(): 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 strlen() function shall compute the number of bytes in the
string to which s points, not including the terminating NUL
character.
The strnlen() function shall compute the smaller of the number of
bytes in the array to which s points, not including any
terminating NUL character, or the value of the maxlen argument.
The strnlen() function shall never examine more than maxlen bytes
of the array pointed to by s.
Возвращаемое значение (Return value)
The strlen() function shall return the length of s; no return
value shall be reserved to indicate an error.
The strnlen() function shall return the number of bytes preceding
the first null byte in the array to which s points, if s contains
a null byte within the first maxlen bytes; otherwise, it shall
return maxlen.
Ошибки (Error)
No errors are defined.
The following sections are informative.
Примеры (Examples)
Getting String Lengths
The following example sets the maximum length of key and data by
using strlen() to get the lengths of those strings.
#include <string.h>
...
struct element {
char *key;
char *data;
};
...
char *key, *data;
int len;
*keylength = *datalength = 0;
...
if ((len = strlen(key)) > *keylength)
*keylength = len;
if ((len = strlen(data)) > *datalength)
*datalength = len;
...
Использование в приложениях (Application usage)
None.
Обоснование (Rationale)
None.
Будущие направления (Future directions)
None.
Смотри также (See also)
wcslen(3p)
The Base Definitions volume of POSIX.1‐2017, string.h(0p)
