215 questions
4
votes
3
answers
462
views
If I am using UTF-8 strings is it risky to use standard string handling that assumes null termination?
From what I understand it is very rare for UTF-8 strings to have embedded NULLs, however there is the case that a person can put a NULL into a Unicode string explicitly with "X\0Y" or ...
- 11.6k
0
votes
1
answer
72
views
Struggling with strings in c - issues will null terminator
I don't understand how there is uninitialised variable access in my code and stack buffer overflow even though the two strings are the same when debugging. When i add a null terminator to str2 it also ...
- 35
1
vote
1
answer
176
views
Bun FFi function fails when I return a null terminated slice from ziglang
I'm implementing a ziglang function to generate a ulid. So far it works when called via a main function. However, when using it with Bun's FFI it fails. (console.log) is an empty string.
Zig
const std ...
- 327
-3
votes
1
answer
218
views
How do I pass a string to a function requiring BYTE*?
I've copied the entirety of this code: https://learn.microsoft.com/en-us/windows/win32/seccrypto/example-c-program--creating-an-hmac
I turned it into a function that accepts two strings. I would like ...
- 1,655
4
votes
1
answer
998
views
What is the difference between '\0' and "\0" in C++ string
I tried to add a null terminator (\0) in a string in two ways.
One using '\0' and another using "\0", and I'm getting different outputs in both cases:
#include <iostream>
#include <...
-1
votes
1
answer
295
views
C++ std::istringstream how to not terminate at '\0' [closed]
There is a function Foo that takes in an input stream of char. I want to call Foo from my function Bar, which takes in a C-style array with size. char is used to represent a byte (not using std::byte ...
- 518
0
votes
1
answer
1k
views
Newlines and null-terminated string in assembly
I am new to assembly and i was looking at a hello world program:
section .data
hello: db 'Hello, World!',10 ; 'Hello, World!' plus a linefeed character
helloLen: equ $-hello ...
- 59
2
votes
1
answer
415
views
Why in C++ are some characters in a multibyte UTF-8 string represented by negative numbers?
The following C++ source code I compile and run in 'Windows 10' and 'Ubuntu' (via 'WSL 2'):
#include <cstring>
#include <iostream>
int main()
{
char str[] = "Hello, привет, 😎!&...
- 311
5
votes
2
answers
3k
views
How to construct a `std::string` from a buffer that may or may not contain a null?
I have a char buffer of known size (for simplicity, let's say a fixed-sized array) from which I would like to construct a std::string. The string in this buffer may be null-terminated or it may run up ...
- 9,746
3
votes
1
answer
270
views
sizeof('\0') null terminator as literal is four bytes but how come in string of characters it takes only one byte?
In c '\0' null-terminator as literal takes 4-bytes (as it's just zero internally) but how come it takes only 1-byte when used in an array of characters or string of characters? Is this compiler magic?
...
- 651
2
votes
1
answer
199
views
How does a String terminate in C?
I know the string in c will be terminated by a character \0.
However, if I do char a[5]="abcd\n" , where would \0 be?
Or do I need to reserve at least one position for \0, whenever I try to ...
- 33
0
votes
1
answer
67
views
parse a char vector to different strings
I have a character vector like
std::vector<char> input({'{', 'a', 'b','}',\0', '{','c','d','}',\0','\0','\0'});
I want to parse this to have strings
string1="ab"
string2="cd"...
- 13
0
votes
2
answers
1k
views
include_str for null terminated string
I need to read a file into a null terminated string at compile time.
Working in Rust OpenGL. I have a shader source code stored in a separate file. The function that will eventually read the source ...
- 673
3
votes
2
answers
185
views
How does realloc treat null bytes in strings?
Relatively new C programmer here. I am reviewing the following code for a tutorial for a side project I am working on to practice C. The point of the abuf struct is to create a string that can be ...
- 103
0
votes
2
answers
89
views
In this solution, if *inputString is a memory address (and the input is a char type) then does *inputString qualify as an array?
I was solving a challenge on CodeSignal in C. Even though the correct libraries where included, I couldn't use the strrev function in the IDE, so I looked up a similar solution and modified it to work....
1
vote
1
answer
3k
views
Append a null terminator to a C++ string
In order to implement a client to some protocol that expects null-byte padding to a specific string, I implemented a functions that pads a string with a specific amount of null bytes:
string padToFill(...
- 33
-1
votes
1
answer
52
views
fprintf on (unterminated?) C-string doesn't spew garbage or segfault -- undefined behavior?
I recently learned (initially from here) how to use mmap to quickly read a file in C, as in this example code:
// main.c
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#...
- 6,435
1
vote
3
answers
2k
views
Put null byte at the end of C array
I have seen this coding pattern multiple times when I am reading the source code of different projects.
z = read(fd, buf, sizeof(buf));
buf[z] = 0;
As far as I know, this is to make sure the c-style ...
- 352
1
vote
1
answer
1k
views
Character array without a null terminator in C
Sometimes I am using sequences of characters (strings) except the null terminator is not needed or wanted, for example if I am using memcpy() and the length is already known. A such, I prefer to omit ...
- 5,110
0
votes
0
answers
353
views
How to save a text file as an array of strings in MIPS
I am creating a program to read a list of strings from a text file, and store them in an array (in memory, but formatted like an array of strings). I am on Windows running MIPS on MARS. The text file ...
- 301
6
votes
3
answers
6k
views
How do I print a vector of chars using fmt?
I have a const std::vector<char> - not null-terminated. I want to print it using the fmt library, without making a copy of the vector.
I would have hoped that specifying the precision would ...
- 137k
3
votes
1
answer
2k
views
What are null-terminated strings? [duplicate]
How are they different from non-null-terminated strings? What is this null that terminates the string? Is it different from NULL? Should I null-terminate my strings myself, or the compiler will do it ...
- 122k
0
votes
1
answer
459
views
Null character is not acting as end of string in assembly (NASM)
In c language we can use '\0' null character as end of string.
#include <stdio.h>
int main() {
char msg[] = "hello\0world";
printf("msg = %s", msg);
}
This code will ...
- 53
-1
votes
1
answer
287
views
Non null-terminated string reading standard input (Assembly Language)
I'm working on making a standard library from scratch in assembly language using NASM. I'm not doing this to use it in huge project, but just to train myself with assembly language making a project ...
- 326
0
votes
2
answers
179
views
In C, how do I extract the different parts of a string that are all separated by the \0 null terminator?
So in the following code, I want to store each section in the corresponding variable. Is there an easier way to do this rather than looping through the entire string char by char and checking if it's ...
- 45
0
votes
0
answers
285
views
nasm zero byte omitted at the end of the string
I am studying Assembly language using this nasm tutorial. Here is the code that prints a string:
SECTION .data
msg db 'Hello!', 0Ah
SECTION .text
global _start
_start:
mov ebx, ...
- 24k
0
votes
0
answers
54
views
in the C ++ stl, does the string container actually contain a string with a closing 0? [duplicate]
string s;
In C ++ string is a vector == pointer to start + length. But will there be a closing 0, as implicitly implied by Prat ?
class String{
private:
char * str; // pointer to string
int len; // ...
- 31
-4
votes
1
answer
503
views
When does a char* ends with null in c?
I have confusion on char* null-termination so i have decided to make a study of cases i can find. Do these string literals end with a null?
char str1[512]="This is a random string"
char *...
- 153
0
votes
2
answers
375
views
Input in Null terminating character array and getting its length
I hava a question.....I have a character array char command[30]. When I use it for input like if I entered !! on console the after input strlength function must give me length of array equals to 2 as ...
0
votes
1
answer
938
views
Checking for string null terminators in C
I know what the null-terminator in C is represented by \0 and has the numerical value of 0. However, when I execute the following code below, the program treats the null terminator as %. I searched ...
- 247
0
votes
3
answers
269
views
How to Replace Leading or Trailing Blank Characters with "X"
Looking for a more efficient way to replace leading and trailing empty spaces (' ') and appending an 'X' to the front for each empty space.. It seems to work ok for trailing spaces but I'd like to ...
0
votes
1
answer
123
views
Avoiding the func(char *) api on embedded
Note:
I heavily changed my question to be more specific, but I will keep the old question at end of the post, in case it is useful to anyone.
New Question
I am developing an embedded application which ...
2
votes
1
answer
276
views
How does a program determine the end of a string?
I can define a new variable like so msg db 'Hello, world!$', or another way msg2 db 'Hello, world!', 0
I know that the end of a string is determined using value 0 in memory. What is symbol $ standing ...
- 4,870
3
votes
2
answers
5k
views
if I initialize a char array to zero/{0} do I have to null terminate?
Say for instance I declare a char array with all values set to zero in the following fashion:
char array[4] = {0};
If I assign it values, for instance:
array[0] = 'A';
array[1] = 'B';
array[2] = 'C';
...
- 57
1
vote
1
answer
513
views
c_str() returns nothing, but string not empty
So, I have a class
class MySuperClass {
public:
std::string buffer;
};
And wants to print buffer to std::cout.
Here's some code about filling string from a file:
MySuperClass msc;
std::fstream file(&...
- 35
0
votes
0
answers
735
views
how to null terminate a string in assembly language?
I am wondering how can I properly null-terminate a string in assembly language: what I did was simply setting movq $0, (position_to_terminate) and I thought this will terminate my string. However, ...
- 213
0
votes
2
answers
3k
views
Does snprintf/sprintf overwrite the terminating-null of the penultimate argument, just like strcat does?
It is clearly written for strcat, e.g. here and here that, in case,
char *strcat(char *s1, const char *s2);
then,
The initial character of s2 overwrites the null character at the end of s1.
But ...
- 3,481
3
votes
2
answers
2k
views
Does '\0' Take Up The Size of a Char? - C
So I am creating a char to string converter and I am creating a string using malloc. I know I need to make space for the null terminating character \0. So do I do char *example = malloc(sizeof(char) + ...
user14160857
0
votes
1
answer
554
views
Weird characters at the end of char array C
I've tried to write an implementation of the Weasel Program. I have compiled three versions, all exactly identical, with the names "weasel.exe", "weasel2.exe", and "weasel3....
0
votes
1
answer
229
views
skip strtok's null terminators safely
I want to use strtok and then return the string after the null terminator that strtok has placed.
char *foo(char *bar)
{
strtok(bar, " ");
return after_strtok_null(bar);
}
/*
examples:
foo(&...
- 247
0
votes
0
answers
59
views
How does Java know the length of strings? [duplicate]
I was searching if Java strings are null-terminated like in C and came across the first answer for this:Does java define string as null terminated?
Basically the link mentions that the length method ...
- 362
1
vote
2
answers
571
views
Two null termination signs at the end of a string in C
I'm learning C via "The C Programming Language" book. During one of the exercises, where it's needed to concatenate two strings, I found that there are two null terminating signs (\0) at the end of a ...
- 13
3
votes
3
answers
416
views
Advantages of null termination vs count variable
I need to use array of graph data, i.e. struct with x and y integers. This array will be passed through many functions, and I need to decide the API choice.
typedef struct {
int x;
int y;
} ...
- 63
2
votes
3
answers
463
views
read null terminated string from byte vector in julia
I have a vector of type UInt8 and fixed length 10. I think it contains a null-terminated string but when I do String(v) it shows the string + all of the zeros of the rest of the vector.
v = zeros(...
- 171
2
votes
1
answer
260
views
Why does this string implementation allocate one more character than there are characters in the string?
String::String(const String& old_str)
{
size = old_str.size;
s = new char[size+1];
Why do we use size+1 here to allocate memory, not size?
- 25
11
votes
3
answers
318
views
What are the specifics of the definition of a string in C?
I am supposed to answer a homework question for one of my classes. Specifically, I am supposed to say if certain arrays in C are considered strings or not. Based on this article (https://www....
- 137
4
votes
2
answers
7k
views
Is it safe to convert function parameter `const char*` to `std::string_view`?
The title almost says it all.
void f(const char*)
to
void f(std::string_view)
Is it safe? if not, what are the pitfalls?
std::string_view semantics dictate that the array isn't necessarily null ...
- 11.5k
0
votes
3
answers
119
views
Unexplainable behaviour when printing out strings in C
The following code works as expected and outputs ABC:
#include <stdio.h>
void printString (char toPrint [100]);
int main()
{
char hello [100];
hello[0] = 'A';
hello[1] = 'B';
hello[2] ...
- 47
4
votes
3
answers
3k
views
A null character '\0' at the end of a string
I have the following code.
#include <stdio.h>
#include <string.h>
#define MAXLINE 1000
int main()
{
int i;
char s[MAXLINE];
for (i = 0; i < 20; ++i) {
s[i] = i + ...
- 91
-1
votes
2
answers
721
views
Char pointer NULL termination and memory allocation [duplicate]
I have the following program : My program compiles fine and gives the output as mentioned below . I have some question on output which is listed at the bottom.
*****************************************...
- 1