C++ How to remove \0 char from std::string

Question

What is the correct way to remove the \0 char´s from a given string.

I´m trying with no success:

std::string msg(data); // Data comes from a remote system connected via socket...
msg.erase(std::remove(msg.begin(), msg.end(), '\0'), msg.end());

This gives compilation error:

error: cannot convert ‘std::__cxx11::basic_string<char>::iterator {aka __gnu_cxx::__normal_iterator<char*, std::__cxx11::basic_string<char> >}’ to ‘const char*’ for argument ‘1’ to ‘int remove(const char*)’

datacomes from a remote system using socket, and contains several pieces of code numbers with /0 in the middle due to source logic.

This isn't a good idea, is it? Since C++11, `std::string` is terminated by `'\0'`, so I think this might not be wise. — erip, Dec 03 '15 at 13:08
I´m receiving a socket data from a remote system that is coming with `\0` chars. That string will be processed in a string comparator logic and later issue mySql inserts/creates that is thowing several errors due to the `\0` presence on the string. So I need to sanitize the string removing these chars. — Mendes, Dec 03 '15 at 13:09
@erip: That '\0' is not part of the data. It's an implementation detail, part of the interface. This would not affect it. — Lightness Races in Orbit, Dec 03 '15 at 13:09
The message contains `int remove(const char*)`, which seems like a different overload. Where did that come from? — Bo Persson, Dec 03 '15 at 13:10
Your approach is [correct](https://stackoverflow.com/questions/20326356/how-to-remove-all-the-occurrences-of-a-char-in-c-string), so something else is wrong. Present your testcase. — Lightness Races in Orbit, Dec 03 '15 at 13:11
Please provide an [mcve] that gives that error. The code you have should work. — NathanOliver, Dec 03 '15 at 13:13
Isn't the base problem that the constructor used here will assume the string ends at the first `'\0'`? [How do you construct a std::string with an embedded null?](http://stackoverflow.com/questions/164168/how-do-you-construct-a-stdstring-with-an-embedded-null) — crashmstr, Dec 03 '15 at 13:21
Perhaps a better approach to construct the string would be using `std::copy_if`. — n. m. could be an AI, Dec 03 '15 at 13:25
`#include ` did the trick... Thanks all... erip: Removing the `\0`´s seens not to be affecting the string in latter logic.... — Mendes, Dec 03 '15 at 13:25
@crashmstr: If you used that particular constructor to create the string then, yes, you'd have a problem. Not this problem though. And you wouldn't use that particular constructor to create the string because that would be stupid. — Lightness Races in Orbit, Dec 03 '15 at 15:40

Walter · Accepted Answer · 2015-12-03T13:31:14.880

8

Your problem arises from a missing #include directive. Your intention was to call std::remove() from <algorithm>, but you inadvertently called std::remove() from <cstdio>. So with

#include <algorithm>

it should work.

(IMHO std::remove(const char*) should be std::remove_file(std::string const&) or at least std::remove_file(const char*).)

edited Dec 03 '15 at 13:31

answered Dec 03 '15 at 13:27

Walter

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C++ How to remove \0 char from std::string

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