ARISE, OLD DEAD THREAD! Hey, this thread is almost legally allowed to drink alcohol in the United States!

Anyways... Uwe Ludwig stumbled upon this and now I am stumbling on this as well. Even if you code in the proper checks on the return value, you will still get a SEGFAULT. There is something weird with lpthreads and getpwuid (and also getlogin) and I don'
t quite know what it is. But, yes... the combo of these two will always cause a SEGFAULT before you can even check the return.

Stats:
- Ubuntu 20.04
- gcc version 9.4.0
- x86_64-linux-gnu

--- SoupGate-Win32 v1.05
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In article <e95d3f27-47ad-4ff4-8429-92821ad3e79en@googlegroups.com>,
stryker2k2 <stryker2k2@gmail.com> wrote:

ARISE, OLD DEAD THREAD! Hey, this thread is almost legally allowed to drink >alcohol in the United States!

Anyways... Uwe Ludwig stumbled upon this and now I am stumbling on this
as well. Even if you code in the proper checks on the return value, you
will still get a SEGFAULT. There is something weird with lpthreads and >getpwuid (and also getlogin) and I don't quite know what it is. But,
yes... the combo of these two will always cause a SEGFAULT before you
can even check the return.

Stats:
- Ubuntu 20.04
- gcc version 9.4.0
- x86_64-linux-gnu

Could you post code & build instructions?

Then we might at least have a chance at understanding what you're talking about, Willis...

--
The randomly chosen signature file that would have appeared here is more than 4 lines long. As such, it violates one or more Usenet RFCs. In order to remain in compliance with said RFCs, the actual sig can be found at the following URL:
http://user.xmission.com/~gazelle/Sigs/RoyDeLoon

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On 1/4/2023 11:28 AM, Kenny McCormack wrote:

In article <e95d3f27-47ad-4ff4-8429-92821ad3e79en@googlegroups.com>, stryker2k2 <stryker2k2@gmail.com> wrote:

ARISE, OLD DEAD THREAD! Hey, this thread is almost legally allowed to drink >> alcohol in the United States!

Anyways... Uwe Ludwig stumbled upon this and now I am stumbling on this
as well. Even if you code in the proper checks on the return value, you
will still get a SEGFAULT. There is something weird with lpthreads and
getpwuid (and also getlogin) and I don't quite know what it is. But,
yes... the combo of these two will always cause a SEGFAULT before you
can even check the return.

Stats:
- Ubuntu 20.04
- gcc version 9.4.0
- x86_64-linux-gnu

Could you post code & build instructions?

Then we might at least have a chance at understanding what you're talking about, Willis...

Mar 5, 2003, 11:49:55 AM

https://groups.google.com/g/comp.unix.programmer/c/hs23vL73-y0

Paul

--- SoupGate-Win32 v1.05
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Paul <nospam@needed.invalid> writes:

On 1/4/2023 11:28 AM, Kenny McCormack wrote:

stryker2k2 <stryker2k2@gmail.com> wrote:

ARISE, OLD DEAD THREAD! Hey, this thread is almost legally allowed to drink >>> alcohol in the United States!

Anyways... Uwe Ludwig stumbled upon this and now I am stumbling on this
as well. Even if you code in the proper checks on the return value, you
will still get a SEGFAULT. There is something weird with lpthreads and
getpwuid (and also getlogin) and I don't quite know what it is. But,
yes... the combo of these two will always cause a SEGFAULT before you
can even check the return.

Stats:
- Ubuntu 20.04
- gcc version 9.4.0
- x86_64-linux-gnu

Could you post code & build instructions?
Then we might at least have a chance at understanding what you're
talking
about, Willis...

Mar 5, 2003, 11:49:55 AM

https://groups.google.com/g/comp.unix.programmer/c/hs23vL73-y0

The program there doesn’t have “the proper checks on the return value”, so it’s presumably not what you’re actually running. Also, -lpthreads
does not exist; the library is -lpthread. So we don’t yet have the build commands you used, either. Obviously, nobody can debug code that you’ve
not shared.

I would suggest using gdb or valgrind to identify where your version
crashes.

--
https://www.greenend.org.uk/rjk/

--- SoupGate-Win32 v1.05
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Paul <nospam@needed.invalid> writes:

On 1/4/2023 11:28 AM, Kenny McCormack wrote:

In article <e95d3f27-47ad-4ff4-8429-92821ad3e79en@googlegroups.com>,
stryker2k2 <stryker2k2@gmail.com> wrote:

ARISE, OLD DEAD THREAD! Hey, this thread is almost legally allowed to drink >>> alcohol in the United States!

Anyways... Uwe Ludwig stumbled upon this and now I am stumbling on this
as well. Even if you code in the proper checks on the return value, you
will still get a SEGFAULT. There is something weird with lpthreads and
getpwuid (and also getlogin) and I don't quite know what it is. But,
yes... the combo of these two will always cause a SEGFAULT before you
can even check the return.

Stats:
- Ubuntu 20.04
- gcc version 9.4.0
- x86_64-linux-gnu

Could you post code & build instructions?
Then we might at least have a chance at understanding what you're talking
about, Willis...

Mar 5, 2003, 11:49:55 AM

https://groups.google.com/g/comp.unix.programmer/c/hs23vL73-y0

That program, with the undefined behaviour removed, but the curious
verbose style kept, is

#include <pwd.h>
#include <unistd.h>
#include <stdio.h>

char *a;

char *getuser(void)
{
char *username;
struct passwd *info;
info = getpwuid(getuid());
username = info->pw_name;
return username;
}

int main(void)
{
a = getuser();
printf(a);
printf("\n");
}

which compiles and runs fine on my system, with either the -pthread or -lpthread option. Of course, since threads are not used, the linker may
simply be omitting the code that caused the problem 19 years ago.

The old post refers to -lpthreads (with and s) and my Ubuntu and gcc are
newer.

--
Ben.

--- SoupGate-Win32 v1.05
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Ben Bacarisse <ben.usenet@bsb.me.uk> writes:

Paul <nospam@needed.invalid> writes:

On 1/4/2023 11:28 AM, Kenny McCormack wrote:

In article <e95d3f27-47ad-4ff4-8429-92821ad3e79en@googlegroups.com>,
stryker2k2 <stryker2k2@gmail.com> wrote:

ARISE, OLD DEAD THREAD! Hey, this thread is almost legally allowed to drink
alcohol in the United States!

Anyways... Uwe Ludwig stumbled upon this and now I am stumbling on this >>>> as well. Even if you code in the proper checks on the return value, you >>>> will still get a SEGFAULT. There is something weird with lpthreads and >>>> getpwuid (and also getlogin) and I don't quite know what it is. But,
yes... the combo of these two will always cause a SEGFAULT before you
can even check the return.

Stats:
- Ubuntu 20.04
- gcc version 9.4.0
- x86_64-linux-gnu

Could you post code & build instructions?
Then we might at least have a chance at understanding what you're talking >>> about, Willis...

Mar 5, 2003, 11:49:55 AM

https://groups.google.com/g/comp.unix.programmer/c/hs23vL73-y0

That program, with the undefined behaviour removed, but the curious
verbose style kept, is

#include <pwd.h>
#include <unistd.h>
#include <stdio.h>

char *a;

char *getuser(void)
{
char *username;
struct passwd *info;
info = getpwuid(getuid());
username = info->pw_name;
return username;
}

int main(void)
{
a = getuser();
printf(a);
printf("\n");
}

which compiles and runs fine on my system, with either the -pthread or >-lpthread option. Of course, since threads are not used, the linker may >simply be omitting the code that caused the problem 19 years ago.

The old post refers to -lpthreads (with and s) and my Ubuntu and gcc are >newer.

The code will fail if there is no password file entry matching
the current uid.

--- SoupGate-Win32 v1.05
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scott@slp53.sl.home (Scott Lurndal) writes:

Ben Bacarisse <ben.usenet@bsb.me.uk> writes:

Paul <nospam@needed.invalid> writes:

On 1/4/2023 11:28 AM, Kenny McCormack wrote:

In article <e95d3f27-47ad-4ff4-8429-92821ad3e79en@googlegroups.com>,
stryker2k2 <stryker2k2@gmail.com> wrote:

ARISE, OLD DEAD THREAD! Hey, this thread is almost legally allowed to drink
alcohol in the United States!

Anyways... Uwe Ludwig stumbled upon this and now I am stumbling on this >>>>> as well. Even if you code in the proper checks on the return value, you >>>>> will still get a SEGFAULT. There is something weird with lpthreads and >>>>> getpwuid (and also getlogin) and I don't quite know what it is. But, >>>>> yes... the combo of these two will always cause a SEGFAULT before you >>>>> can even check the return.

Stats:
- Ubuntu 20.04
- gcc version 9.4.0
- x86_64-linux-gnu

Could you post code & build instructions?
Then we might at least have a chance at understanding what you're talking >>>> about, Willis...

Mar 5, 2003, 11:49:55 AM

https://groups.google.com/g/comp.unix.programmer/c/hs23vL73-y0

That program, with the undefined behaviour removed, but the curious
verbose style kept, is

#include <pwd.h>
#include <unistd.h>
#include <stdio.h>

char *a;

char *getuser(void)
{
char *username;
struct passwd *info;
info = getpwuid(getuid());
username = info->pw_name;
return username;
}

int main(void)
{
a = getuser();
printf(a);
printf("\n");
}

which compiles and runs fine on my system, with either the -pthread or >>-lpthread option. Of course, since threads are not used, the linker may >>simply be omitting the code that caused the problem 19 years ago.

The old post refers to -lpthreads (with and s) and my Ubuntu and gcc are >>newer.

The code will fail if there is no password file entry matching
the current uid.

Sure, but if that's what the OP is observing, then I can't see the
connection to the pthread library.

--
Ben.

--- SoupGate-Win32 v1.05
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