Newline in ANSI-C standard functions Post: 303020120

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Top Forums Programming Newline in ANSI-C standard functions Post 303020120 by jim mcnamara on Friday 13th of July 2018 08:50:12 PM

07-13-2018

Registered User

You are depending on the existence of a terminating NUL. You write 128 total and leave no room in the shorter string str1. You leave no terminating NUL. strcpy printf and lots of other functions depend on the existence of correclty terminated strings. Your sis not.

memset does not care where the end of a string is. Make str1[129], then write less than a total of 129 to str1. Or write fewer characters total to str1.

You are getting undefined behavior. That means I cannot know what your environment is doing or has done. You cannot ever know either. It could crash the program, compose a poem, or order a pizza.

I am guessing. If str1 precedes str2 in memory and each one is word-aligned, then the last character you write to str1[128] effectively cause the end of of str1 to be the actual end of str2. As far as strcpy, printf and so on are concerned.

So, when you exchange order or the two variables you change observed behavior.

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LEARN ABOUT PHP

strcoll

STRCOLL(3)								 1								STRCOLL(3)

strcoll - Locale based string comparison

SYNOPSIS

       int strcoll (string  $str1, string  $str2)

DESCRIPTION

	Note that this comparison is case sensitive, and unlike strcmp(3) this function is not binary safe.

       strcoll(3)  uses  the  current  locale  for doing the comparisons. If the current locale is C or POSIX, this function is equivalent to str-
       cmp(3).

PARAMETERS

	      o $str1
		- The first string.

	      o $str2
		- The second string.

RETURN VALUES

	Returns < 0 if $str1 is less than $str2; > 0 if $str1 is greater than $str2, and 0 if they are equal.

CHANGELOG

       +--------+------------------------------------+
       |Version |				     |
       |	|				     |
       |	|	     Description	     |
       |	|				     |
       +--------+------------------------------------+
       | 4.2.3	|				     |
       |	|				     |
       |	|  This function now works on win32. |
       |	|				     |
       +--------+------------------------------------+
SEE ALSO

       preg_match(3), strcmp(3), strcasecmp(3), substr(3), stristr(3), strncasecmp(3), strncmp(3), strstr(3), setlocale(3).

PHP Documentation Group 														STRCOLL(3)

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