A standard C function that returns the length of a string.
This function calculates the length of the string, excluding the terminating null byte \0. It is defined in the <string.h> standard header.
Questions tagged [strlen]
692 questions
22
votes
3 answers
Best way to get length of const char * in c++
i know two way's to get length of const char *
const char * str = "Hello World !";
int Size = 0;
while (str[Size] != '\0') Size++;
and other way is very simple
const char * str = "Hello World !";
size_t Size = strlen(str);
but i don't want to use…
JamesAlb
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21
votes
8 answers
How to find the length of argv[] in C
#include
#include
#include
int main(int argc, char *argv[]){
int fir; //badly named loop variable
char *input[] = calloc( strlen(argv), sizeof(char)); //initializing an array
for( fir = 1; fir<…
user1787351
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20
votes
5 answers
which C++ header file declares strlen?
Which library does strlen() belong to?
Does it belong to cstring? or string?
I tried the following code, and it does work:
include
using namespace std;
//withou include
int main() {
char * str="abc";
…
user2756494
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19
votes
2 answers
Why reimplement strlen as loop+subtraction?
Inspired by this question about the following code from SQLite3:
static int strlen30(const char *z){
const char *z2 = z;
while( *z2 ){ z2++; }
return 0x3fffffff & (int)(z2 - z);
}
that is accompanied by a commit message saying this…
sharptooth
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18
votes
1 answer
How does the strlen function work internally?
How does strlen() work internally? Are there any inherent bugs in the function?
Manu
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18
votes
6 answers
Check if php get variable is set to anything?
I need to check if variables are set to something. Up till now I have been using strlen(), but that is really embarrassing as I am pretty sure that is not a very efficient function to be using over an over again.
How do I perform this sort of check…
Amy Neville
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16
votes
4 answers
can I count on my compiler to optimize strlen on const char *?
In my SAX xml parsing callback (XCode 4, LLVM), I am doing a lot of calls to
this type of code:
static const char* kFoo = "Bar";
void SaxCallBack(char* sax_string,.....)
{
if ( strcmp(sax_string, kFoo, strlen(kFoo) ) == 0)
{
}
…
Jacko
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14
votes
6 answers
strlen() and UTF-8 encoding
Assuming UTF-8 encoding, and strlen() in PHP, is it possible that this string has a length of 4?
I'm only interested to know about strlen(), not other functions
This is the string:
$1�2
I have tested it on my own computer, and I have verified…
Jon Lyles
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12
votes
4 answers
Why does this function return the correct length of a string? (Incrementing a char pointer)
This is a function that counts the number of characters in a string:
int str_len(const char* s) {
int i = 0;
while(*(s++)) {
i++;
}
return i;
}
Why does this return the correct length?
Let's say I call this function with a…
lor
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12
votes
3 answers
C++11 char16_t strlen-equivalent function
I have a simple question:
Is there a way to do a strlen()-like count of characters in zero-terminated char16_t array?
NoSenseEtAl
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12
votes
9 answers
C strlen() implementation in one line of code
Yesterday I was at interview and was asked to implement strlen() in C without using any standard functions, all by hands. As an absolute amateur, I implemented primitive version with while loop. Looking at this my interviewer said that it can be…
Olex
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9
votes
5 answers
How can I use strlen in php for Persian?
I have this code:
$string = 'علی';
echo strlen($string);
Since $string has 3 Persian characters, output must be 3 but I get 6.
علی has 3 characters. Why my output is 6 ?
How can I use strlen() in php for Persian with real output?
user3932710
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9
votes
3 answers
strlen performance implementation
This is a multipurpose question:
How does this compare to the glibc strlen implementation?
Is there a better way to to this in general and for autovectorization.
#include
#include
#include
#include…
nwmcsween
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8
votes
9 answers
Is There A Difference Between strlen()==0 and empty()?
I was looking at some form validation code someone else had written and I saw this:
strlen() == 0
When testing to see if a form variable is empty I use the empty() function. Is one way better than the other? Are they functionally equivalent?
red4d
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8
votes
5 answers
How to strcpy and return number of copied characters?
I want to copy a null-terminated string to another location and want to know how long the copied string was. Efficiency is of utmost importance. There ist the strcpy function which can achieve this, but it does not return how many characters are…
gexicide
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