Are all c libraries in c++ too

Question

Hi I am running this code on the visual studio 2022 .But it is saying #include <unistd.h> cannot be opened. Basically it is c code which I am running in cpp environment.

#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>

int  main()
{
    int id;
    id = fork();
    if (id < 0) {
        printf(" Error \n");
        return (1);
    }
    else if (id == 0)
        printf("Child\n");
    else
        printf("Parent \n");

    return 0;


}

So i am confusing may be all c libraries are not included in cpp language. And in case i run this program in gcc this is saying fork in not defined???

I have tried to run this code on three compilers in dev cpp , visual studio 2022 and gcc but error have been thrown.

The `uni` prefix in `unistd.h` stands for UNIX. My guess is you're building in Windows? It won't have Unix headers, or the `fork` call for that matter. — Some programmer dude, Dec 04 '22 at 15:27
for example for `stdio.h` there is a C++ header available that you should use `cstdio`. — 463035818_is_not_an_ai, Dec 04 '22 at 15:28
C and C++ are two different languages. C++ is not a superset of C. What compiles as C does not necessarily compile as C++ (and vice versa, though thats usually the lesser surprise) — 463035818_is_not_an_ai, Dec 04 '22 at 15:28
I think you'll find that if you try compiling as C in the same environment, it still won't work. So the question doesn't address your problem. "Why doesn't this C thing work in C++?" Um, the C thing doesn't work either. — Raymond Chen, Dec 04 '22 at 15:31
@463035818_is_not_a_number that's a bad example. Better examples are `stdbool.h`, `tgmath.h`, `complex.h`... which don't exist in C++. To some extent `stdatomic.h` and `stdalign.h` can also be included — phuclv, Dec 04 '22 at 15:36
Related: [https://stackoverflow.com/questions/33675953/best-way-to-get-around-fork-with-mingw-64](https://stackoverflow.com/questions/33675953/best-way-to-get-around-fork-with-mingw-64) — drescherjm, Dec 04 '22 at 15:58
Also: [https://stackoverflow.com/questions/985281/what-is-the-closest-thing-windows-has-to-fork](https://stackoverflow.com/questions/985281/what-is-the-closest-thing-windows-has-to-fork) — drescherjm, Dec 04 '22 at 15:59
On windows you could use WSL from Visual Studio or VSCode and compile this code directly on linux: [https://learn.microsoft.com/en-us/cpp/build/walkthrough-build-debug-wsl2?view=msvc-170](https://learn.microsoft.com/en-us/cpp/build/walkthrough-build-debug-wsl2?view=msvc-170) — drescherjm, Dec 04 '22 at 16:00

score 0 · Answer 1 · answered Dec 04 '22 at 15:30

0

unistd.h is a unix file, if you are running this on Windows you can not use that header file.

answered Dec 04 '22 at 15:30

Are all c libraries in c++ too

1 Answers1