01-27-2009
If he uses something other than NULLs to terminate strings, then he needs his own strlen. If he already has given lengths for data, he doesn't need strlen. But if he thinks writing his own will be faster than the library function that's not too likely. gcc in particular has intrinsics that can reduce it to a vanishingly small number of instructions in some cases and architectures.
He does have a point, though, in that sockets deliver raw data, not strings per-se. They only have nulls on the end if you send nulls, which is not something you want to rely on with data from an uncontrolled outside source. better to deal with data in random lengths than measure it every time.
Last edited by Corona688; 01-27-2009 at 01:13 AM..
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STRLEN(3P) POSIX Programmer's Manual STRLEN(3P)
PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the correspond-
ing Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.
NAME
strlen - get string length
SYNOPSIS
#include <string.h>
size_t strlen(const char *s);
DESCRIPTION
The strlen() function shall compute the number of bytes in the string to which s points, not including the terminating null byte.
RETURN VALUE
The strlen() function shall return the length of s; no return value shall be reserved to indicate an error.
ERRORS
No errors are defined.
The following sections are informative.
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;
...
APPLICATION USAGE
None.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
The Base Definitions volume of IEEE Std 1003.1-2001, <string.h>
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technol-
ogy -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 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 at http://www.opengroup.org/unix/online.html .
IEEE
/The Open Group 2003 STRLEN(3P)