Re: [PATCH v3 3/3] linux: Add pidfd_getpid

[Andreas Schwab <schwab@suse.de>]

On Mai 16 2023, Adhemerval Zanella via Libc-alpha wrote:

> diff --git a/NEWS b/NEWS
> index aaecdc1c5b..7334bb49e9 100644
> --- a/NEWS
> +++ b/NEWS
> @@ -47,6 +47,10 @@ Major new features:
>    return a process ID, it returns a file descriptor that can be used along
>    other pidfd functions.
>  
> +* On Linux, the pidfd_getpid has been added.  It allows to retrieve the

the pidfd_getpid function

> diff --git a/manual/process.texi b/manual/process.texi
> index 93e0ab5fb7..25417dce0d 100644
> --- a/manual/process.texi
> +++ b/manual/process.texi
> @@ -33,6 +33,7 @@ primitive functions to do each step individually instead.
>  * Process Creation Concepts::   An overview of the hard way to do it.
>  * Process Identification::      How to get the process ID of a process.
>  * Creating a Process::          How to fork a child process.
> +* Querying a Process::          How to query a child process.
>  * Executing a File::            How to make a process execute another program.
>  * Process Completion::          How to tell when a child process has completed.
>  * Process Completion Status::   How to interpret the status value
> @@ -389,6 +390,37 @@ Acts as @code{_Fork}, where it does not invoke any callbacks registered with
>  
>  This function is specific to Linux.
>  
> +@node Querying a Process
> +@section Querying a Process
> +
> +The @code{pidfd_fork} function returned file descriptor can be used to query
> +for process extra information.

The file descriptor returned by the @code{pidfd_fork} function

> +@deftypefun pid_t pidfd_getpid (int @var{fd})
> +@standards{GNU, sys/pidfd.h}
> +@safety{@prelim{}@mtsafe{}@assafe{}@acsafe{}}
> +
> +The @code{pidfd_getpid} retrieves the process ID associated with process file

The @code{pidfd_getpid} function

> +If the operation fails, @code{pidfd_getpid} return a value of @code{-1} and the

returns @code{-1}

-- 
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."