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file system lib for C

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  file system lib for C Thiago Adams <thiago.adams@gmail.com> - 2018-12-23 10:12 -0800
    Re: file system lib for C Clark Smith <noaddress@nowhere.net> - 2018-12-23 20:20 +0000
      Re: file system lib for C James Kuyper <jameskuyper@alumni.caltech.edu> - 2018-12-23 16:41 -0500
      Re: file system lib for C Thiago Adams <thiago.adams@gmail.com> - 2018-12-30 10:33 -0800
        Re: file system lib for C nobody@example.org (Scott) - 2018-12-30 20:42 +0000
          Re: file system lib for C Thiago Adams <thiago.adams@gmail.com> - 2018-12-30 12:52 -0800
    Re: file system lib for C rbowman <bowman@montana.com> - 2018-12-23 13:38 -0700
      Re: file system lib for C Keith Thompson <kst-u@mib.org> - 2018-12-23 13:39 -0800
        Re: file system lib for C Thiago Adams <thiago.adams@gmail.com> - 2018-12-30 11:09 -0800
          Re: file system lib for C "Chris M. Thomasson" <invalid_chris_thomasson@invalid.invalid> - 2018-12-30 14:59 -0800
          Re: file system lib for C rbowman <bowman@montana.com> - 2018-12-30 16:09 -0700
    Re: file system lib for C nobody@example.org (Scott) - 2018-12-23 20:51 +0000
    Re: file system lib for C jgh@mdfs.net - 2018-12-30 09:15 -0800
      Re: file system lib for C Thiago Adams <thiago.adams@gmail.com> - 2018-12-30 10:34 -0800

#138979 — file system lib for C

I started a new project on github that is a clone
of C++ file system but for C. (I will add the functions I need 
on demand.)
This is something I miss for C.

If you don't know what std::filesystem is:

https://en.cppreference.com/w/cpp/filesystem

Some changes have to be made to adapt the code to C.

I am adding a "fs_" suffix and copying functions
that don´t use exceptions.
 
C++ has a error object I am not sure what is the best
design for C. 

For instance:

bool create_directory( const std::filesystem::path& p, std::error_code& ec ) noexcept;

I don't think error_code deserves a exactly copy 
https://en.cppreference.com/w/cpp/error/error_code
because it is too complicated.

Suggestions how to adapt this for C and contributions/critics
are welcome.

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#138992

On Sun, 23 Dec 2018 10:12:24 -0800, Thiago Adams wrote:

> I started a new project on github that is a clone of C++ file system but
> for C. (I will add the functions I need on demand.)
> This is something I miss for C.
> 
> If you don't know what std::filesystem is:
> 
> https://en.cppreference.com/w/cpp/filesystem

	Looking into this link, doesn't C (at least under Unix) already 
offers roughly the same capabilities?

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#139000

On 12/23/18 15:20, Clark Smith wrote:
> On Sun, 23 Dec 2018 10:12:24 -0800, Thiago Adams wrote:
> 
>> I started a new project on github that is a clone of C++ file system but
>> for C. (I will add the functions I need on demand.)
>> This is something I miss for C.
>>
>> If you don't know what std::filesystem is:
>>
>> https://en.cppreference.com/w/cpp/filesystem
> 
> 	Looking into this link, doesn't C (at least under Unix) already 
> offers roughly the same capabilities?

Unix provides a C interface for doing such things, but C itself does not.

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#139250

On Sunday, December 23, 2018 at 6:20:19 PM UTC-2, Clark Smith wrote:
> On Sun, 23 Dec 2018 10:12:24 -0800, Thiago Adams wrote:
> 
> > I started a new project on github that is a clone of C++ file system but
> > for C. (I will add the functions I need on demand.)
> > This is something I miss for C.
> > 
> > If you don't know what std::filesystem is:
> > 
> > https://en.cppreference.com/w/cpp/filesystem
> 
> 	Looking into this link, doesn't C (at least under Unix) already 
> offers roughly the same capabilities?

Sure. Windows and Linux have it.
But for cross platform code we need a common API.
C++ has added this filesystem lib.

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#139254

On Sun, 30 Dec 2018 10:33:31 -0800 (PST), Thiago Adams
<thiago.adams@gmail.com> wrote:

>On Sunday, December 23, 2018 at 6:20:19 PM UTC-2, Clark Smith wrote:
>> On Sun, 23 Dec 2018 10:12:24 -0800, Thiago Adams wrote:
>> 
>> > I started a new project on github that is a clone of C++ file system but
>> > for C. (I will add the functions I need on demand.)
>> > This is something I miss for C.
>> > 
>> > If you don't know what std::filesystem is:
>> > 
>> > https://en.cppreference.com/w/cpp/filesystem
>> 
>> 	Looking into this link, doesn't C (at least under Unix) already 
>> offers roughly the same capabilities?
>
>Sure. Windows and Linux have it.
>But for cross platform code we need a common API.
>C++ has added this filesystem lib.

Well...outside of mini/main class systems, where do you find any
platform today that isn't Windows or, at heart, Unix-like?

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#139255

On Sunday, December 30, 2018 at 6:41:07 PM UTC-2, Scott wrote:
> On Sun, 30 Dec 2018 10:33:31 -0800 (PST), Thiago Adams
>  wrote:
> 
> >On Sunday, December 23, 2018 at 6:20:19 PM UTC-2, Clark Smith wrote:
> >> On Sun, 23 Dec 2018 10:12:24 -0800, Thiago Adams wrote:
> >> 
> >> > I started a new project on github that is a clone of C++ file system but
> >> > for C. (I will add the functions I need on demand.)
> >> > This is something I miss for C.
> >> > 
> >> > If you don't know what std::filesystem is:
> >> > 
> >> > https://en.cppreference.com/w/cpp/filesystem
> >> 
> >> 	Looking into this link, doesn't C (at least under Unix) already 
> >> offers roughly the same capabilities?
> >
> >Sure. Windows and Linux have it.
> >But for cross platform code we need a common API.
> >C++ has added this filesystem lib.
> 
> Well...outside of mini/main class systems, where do you find any
> platform today that isn't Windows or, at heart, Unix-like?

I need more than mkdir and the other APIS are different
for other functions.
For instance see directory_iterator.

https://github.com/thradams/filesystem/blob/master/fs.h
https://github.com/thradams/filesystem/blob/master/fs.c

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#138995

On 12/23/2018 11:12 AM, Thiago Adams wrote:
> bool create_directory( const std::filesystem::path& p, std::error_code& ec ) noexcept;
>
> I don't think error_code deserves a exactly copy
> https://en.cppreference.com/w/cpp/error/error_code
> because it is too complicated.
>
> Suggestions how to adapt this for C and contributions/critics
> are welcome.
>

I'm not sure I understand your question but

#include <errno.h>
#include <string.h>
................
if (mkdir(path, mode) == -1) {
    fprintf(stderr, "mkdir failed: %s\n", strerror(errno));
    /* do whatever error recovery you need */
}


Check the man pages for the appropriate return. Ones that return an int 
like mkdir() typically return -1 for an error condition. Those like 
fopen() which return a FILE* return a null.

The <string.h> include is for strerror() which returns a descriptive 
string.  That's generally more useful than  'the error was 23'.

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#138999

rbowman <bowman@montana.com> writes:
> On 12/23/2018 11:12 AM, Thiago Adams wrote:
>> bool create_directory( const std::filesystem::path& p, std::error_code& ec ) noexcept;
>>
>> I don't think error_code deserves a exactly copy
>> https://en.cppreference.com/w/cpp/error/error_code
>> because it is too complicated.
>>
>> Suggestions how to adapt this for C and contributions/critics
>> are welcome.
>>
>
> I'm not sure I understand your question but
>
> #include <errno.h>
> #include <string.h>
> ................
> if (mkdir(path, mode) == -1) {
>     fprintf(stderr, "mkdir failed: %s\n", strerror(errno));
>     /* do whatever error recovery you need */
> }

mkdir() requires `#include <sys/stat.h>`, which is POSIX-specific and
not part of the C standard.  C++'s std::filesystem (new in C++17) is, I
think, intended to be more general.

[...]

-- 
Keith Thompson (The_Other_Keith) kst@mib.org  <http://www.ghoti.net/~kst>
Will write code for food.
"We must do something.  This is something.  Therefore, we must do this."
    -- Antony Jay and Jonathan Lynn, "Yes Minister"

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#139252

On Sunday, December 23, 2018 at 7:39:13 PM UTC-2, Keith Thompson wrote:
> rbowman  writes:
> > On 12/23/2018 11:12 AM, Thiago Adams wrote:
> >> bool create_directory( const std::filesystem::path& p, std::error_code& ec ) noexcept;
> >>
> >> I don't think error_code deserves a exactly copy
> >> https://en.cppreference.com/w/cpp/error/error_code
> >> because it is too complicated.
> >>
> >> Suggestions how to adapt this for C and contributions/critics
> >> are welcome.
> >>
> >
> > I'm not sure I understand your question but
> >
> > #include <errno.h>
> > #include <string.h>
> > ................
> > if (mkdir(path, mode) == -1) {
> >     fprintf(stderr, "mkdir failed: %s\n", strerror(errno));
> >     /* do whatever error recovery you need */
> > }
> 
> mkdir() requires `#include <sys/stat.h>`, which is POSIX-specific and
> not part of the C standard.  C++'s std::filesystem (new in C++17) is, I
> think, intended to be more general.
> 
> [...]
> 


Some libraries like atomic and threads first were
added into C++ and later added into C.


Compare:

https://en.cppreference.com/w/cpp/thread

with

https://en.cppreference.com/w/c/thread

In my cross platform code I need create dir, iterate etc.
So I thought a filesystem for C could be based on the C++ 
version, similar of what happened with threads.

The advantage if that you have to learn just once.

I am not sure if in this case we have enough benefits
cloning C++.  Maybe traditional mkdir is better.

Windows has _mkdir that is very similar.

https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/mkdir-wmkdir?view=vs-2017

and also sets errno.

I could create fs_mkdir that calls _mkdir on windows and mkdir on linux.

But I also need a way to iterate directories and more.


I want to have at least 3 projects for cross plataform
code.

1 - console (https://github.com/thradams/conio)
2 - filesystem (https://github.com/thradams/filesystem)
3 - sockets (https://github.com/thradams/Sockets)


I already use a project called tinycthread 
https://github.com/tinycthread/tinycthread
that has what I need for threads.


For sockets, even when windows has the same function,
lets say 'recv' the way of reporting error is different.
Linux sets errno and windows has  WSAGetLastError .


http://man7.org/linux/man-pages/man2/recv.2.html

https://docs.microsoft.com/en-us/windows/desktop/api/winsock/nf-winsock-recv

The error number is also different

Windows:
WSAEACCES 10013

Linux
EACCES 13

So in this case I may add a parameter to return the error instead
of use errno or WSAGetLastError.
Another option could be translate WSAEACCES and set errno then both
function would have the same behavior.

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#139268

On 12/30/2018 11:09 AM, Thiago Adams wrote:
> On Sunday, December 23, 2018 at 7:39:13 PM UTC-2, Keith Thompson wrote:
>> rbowman  writes:
>>> On 12/23/2018 11:12 AM, Thiago Adams wrote:
>>>> bool create_directory( const std::filesystem::path& p, std::error_code& ec ) noexcept;
>>>>
>>>> I don't think error_code deserves a exactly copy
>>>> https://en.cppreference.com/w/cpp/error/error_code
>>>> because it is too complicated.
>>>>
>>>> Suggestions how to adapt this for C and contributions/critics
>>>> are welcome.
>>>>
>>>
>>> I'm not sure I understand your question but
>>>
>>> #include <errno.h>
>>> #include <string.h>
>>> ................
>>> if (mkdir(path, mode) == -1) {
>>>      fprintf(stderr, "mkdir failed: %s\n", strerror(errno));
>>>      /* do whatever error recovery you need */
>>> }
>>
>> mkdir() requires `#include <sys/stat.h>`, which is POSIX-specific and
>> not part of the C standard.  C++'s std::filesystem (new in C++17) is, I
>> think, intended to be more general.
>>
>> [...]
>>
> 
> 
> Some libraries like atomic and threads first were
> added into C++ and later added into C.
[...]

How many compilers support C11 threads and atomics? So far, I can only 
find one.

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#139269

On 12/30/2018 12:09 PM, Thiago Adams wrote:
> Windows has _mkdir that is very similar.
>
> https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/mkdir-wmkdir?view=vs-2017
>
> and also sets errno.

I don't remember exactly when MS got religion but you'll see a number of 
POSIX functions that were supported with a disclaimer:

This POSIX function is deprecated. Use the ISO C++ conformant _xxxx instead.

It would be interesting to look under the hood to see if anything really 
has changed. Life would be simpler if MS had been fully POSIX and ISO 
compliant all along.

Also, as you mention, they got into sockets relatively late, did it 
their own way, and it doesn't always work the way you expect. It keeps 
cross platform work interesting.

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#138996

On Sun, 23 Dec 2018 10:12:24 -0800 (PST), Thiago Adams
<thiago.adams@gmail.com> wrote:

>
>I started a new project on github that is a clone
>of C++ file system but for C. (I will add the functions I need=20
>on demand.)
>This is something I miss for C.
>
>If you don't know what std::filesystem is:
>
>https://en.cppreference.com/w/cpp/filesystem
...
>bool create_directory( const std::filesystem::path& p, std::error_code& ec =
>) noexcept;
...
>Suggestions how to adapt this for C and contributions/critics
>are welcome.

One question that immediately occurs:
is there something wrong with mkdir(2)?
What problem do you perceive that you're trying to solve?

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#139247

Thiago Adams wrote:
> I am adding a "fs_" suffix and copying functions
> that don´t use exceptions.

That's a prefix.

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#139251

On Sunday, December 30, 2018 at 3:15:26 PM UTC-2, j...@mdfs.net wrote:
> Thiago Adams wrote:
> > I am adding a "fs_" suffix and copying functions
> > that don´t use exceptions.
> 
> That's a prefix.

Thanks. :)

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