PROLOG | NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | EXAMPLES | APPLICATION USAGE | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT

STRLEN(3P)                POSIX Programmer's Manual               STRLEN(3P)

PROLOG         top

       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.

NAME         top

       strlen, strnlen — get length of fixed size string

SYNOPSIS         top

       #include <string.h>

       size_t strlen(const char *s);
       size_t strnlen(const char *s, size_t maxlen);

DESCRIPTION         top

       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.1‐2008 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 the 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.

RETURN VALUE         top

       The strlen() function shall return the length of s; no return value
       shall be reserved to indicate an error.

       The strnlen() function shall return an integer containing the smaller
       of either the length of the string pointed to by s or maxlen.

ERRORS         top

       No errors are defined.

       The following sections are informative.

EXAMPLES         top

   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;
           ...

APPLICATION USAGE         top

       None.

RATIONALE         top

       None.

FUTURE DIRECTIONS         top

       None.

SEE ALSO         top

       wcslen(3p)

       The Base Definitions volume of POSIX.1‐2008, string.h(0p)

COPYRIGHT         top

       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1, 2013 Edition, Standard for Information
       Technology -- Portable Operating System Interface (POSIX), The Open
       Group Base Specifications Issue 7, Copyright (C) 2013 by the
       Institute of Electrical and Electronics Engineers, Inc and The Open
       Group.  (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1
       applied.) In the event of any discrepancy between this version and
       the original IEEE and The Open Group Standard, the original IEEE and
       The Open Group Standard is the referee document. The original
       Standard can be obtained online at http://www.unix.org/online.html .

       Any typographical or formatting errors that appear in this page are
       most likely to have been introduced during the conversion of the
       source files to man page format. To report such errors, see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .

IEEE/The Open Group                 2013                          STRLEN(3P)

Pages that refer to this page: string.h(0p)localeconv(3p)strnlen(3p)wcslen(3p)