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strlen(3p) — Linux manual page

STRLEN(3P)              POSIX Programmer's ManualSTRLEN(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_tmaxlen);

DESCRIPTION        top

       Forstrlen(): 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.       Thestrlen() function shall compute the number of bytes in the       string to whichs points, not including the terminating NUL       character.       Thestrnlen() function shall compute the smaller of the number of       bytes in the array to whichs points, not including any       terminating NUL character, or the value of themaxlen argument.       Thestrnlen() function shall never examine more thanmaxlen bytes       of the array pointed to bys.

RETURN VALUE        top

       Thestrlen() function shall return the length ofs; no return       value shall be reserved to indicate an error.       Thestrnlen() function shall return the number of bytes preceding       the first null byte in the array to whichs points, ifs contains       a null byte within the firstmaxlen bytes; otherwise, it shall       returnmaxlen.

ERRORS        top

       No errors are defined.The following sections are informative.

EXAMPLES        top

Getting String Lengths       The following example sets the maximum length ofkey anddata by       usingstrlen() 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.1‐2017,string.h(0p)

COPYRIGHT        top

       Portions of this text are reprinted and reproduced in electronic       form from IEEE Std 1003.1-2017, Standard for Information       Technology -- Portable Operating System Interface (POSIX), The       Open Group Base Specifications Issue 7, 2018 Edition, Copyright       (C) 2018 by the Institute of Electrical and Electronics Engineers,       Inc and The Open Group.  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 athttp://www.opengroup.org/unix/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, seehttps://www.kernel.org/doc/man-pages/reporting_bugs.html .IEEE/The Open Group                2017STRLEN(3P)

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

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