null-character

问题 I have read this post. But when I tried: printf("before null %c after null\n", 0); // (ASCII=0) != '\0' ?? instead of getting: before null I got: before null after null So my question is: Is ASCII value 0 actually equal to '\0'? 回答1: Is ASCII value 0 actually equal to \0 ? Yes The differences in how the strings are stored in memory and handled by functions like printf() are important. "before null %c after null\n" "before null \0 after null\n" Both are stored in memory with an implicit \0

问题 I have read this post. But when I tried: printf("before null %c after null\n", 0); // (ASCII=0) != '\0' ?? instead of getting: before null I got: before null after null So my question is: Is ASCII value 0 actually equal to '\0'? 回答1: Is ASCII value 0 actually equal to \0 ? Yes The differences in how the strings are stored in memory and handled by functions like printf() are important. "before null %c after null\n" "before null \0 after null\n" Both are stored in memory with an implicit \0

问题 Can strings in SQLite 3 include NUL characters? If the answer to 1 is "yes", how can they be written in SQL queries? SQLite doesn't seem to have chr or char functions. 回答1: In general, no - SQLite internally is not 8-bit clean, probably due to its Tcl heritage. While NULs do not cause corruption problems, SQLite typically stops processing strings at the first embedded NUL character. This is true even for operators such as GLOB. For instance, you cannot match a BLOB column with GLOB when you

问题 I am telneting to my server, which answers to me with messages and at the end of each message is appended hex00 (null character) which cannot be read. I tried searching through and through, but can't seem to make it work, a simple example: from telnetlib import Telnet connection = Telnet('localhost', 5001) connection.write('aa\n') connection.read_eager() This returns an output: 'Fail - Command aa not found.\n\r' whereas there should be sth like: 'Fail - Command aa not found.\n\r\0' Is there

问题 Suppose I want to read from stdin , and let the user input strings that contain null characters. Is this possible with string-input functions like fgets or gets_s ? Or do I have to use e.g. fgetc or fread ? Someone here wanted to do this. 回答1: Is it possible to read null characters correctly using fgets or gets_s? As some of the other answers show, the answer is apparently "Yes -- just barely." Similarly, it is possible to hammer in nails using a screwdriver. Similarly, it is possible to

问题 Suppose I want to read from stdin , and let the user input strings that contain null characters. Is this possible with string-input functions like fgets or gets_s ? Or do I have to use e.g. fgetc or fread ? Someone here wanted to do this. 回答1: Is it possible to read null characters correctly using fgets or gets_s? As some of the other answers show, the answer is apparently "Yes -- just barely." Similarly, it is possible to hammer in nails using a screwdriver. Similarly, it is possible to

问题 Here is my code: void func(char c) { char * ptr = &c; size_t len = strlen(ptr); printf("len - %d\n", len); } len is always printed as 1. strlen(..) determines the length of a char array by finding the null character ( \0 ) at the end of it. Here ptr is initialized with just the address of a single character ( c ). c does not contain any null characters. How does ptr get the length? 回答1: You cannot use strlen() on a pointer that does not point to a null-terminated array. It invokes undefined

问题 Suppose we are doing a multiline regex pattern search on a bunch of files and we want to extract the matches from grep. By default, grep outputs matches separated by newlines, but since we are doing multiline patterns this creates the inconvenience that we cannot easily extract the individual matches. Example grep -rzPIho '}\n\n\w\w\b' | od -a Depending on the files in your filetree, this may yield an output like 0000000 } nl nl m y nl } nl nl i f nl } nl nl m 0000020 y nl } nl nl m y nl } nl

问题 I've been reading up on this post: bash "for in" looping on null delimited string variable to see if I would be able to handle arbitrary text containing spaces inside an array. Based on the post above this works fine: while IFS= read -r -d '' myvar; do echo $myvar; done < <(find . -type f -print0) To check my understanding I also did this (which still works fine): while IFS= read -r -d '' myvar; do echo $myvar; done < <(printf "%s\0" 'a b' 'c d') However, then I attempt storing the output in

问题 I am brushing up on my C++ and stumbled across a curious behavior in regards to strings, character arrays, and the null character ( '\0' ). The following code: #include <iostream> using namespace std; int main() { cout << "hello\0there"[6] << endl; char word [] = "hello\0there"; cout << word[6] << endl; string word2 = "hello\0there"; cout << word2[6] << endl; return 0; } produces the output: > t > t > What is going on behind the scenes? Why does the string literal and the declared char array