getunwind

GETUNWIND(2)                Linux Programmer's Manual               GETUNWIND(2)



NAME
       getunwind - copy the unwind data to caller's buffer

SYNOPSIS
       #include <syscall.h>
       #include <linux/unwind.h>

       long getunwind(void *buf, size_t buf_size);

       Note: There is no glibc wrapper for this system call; see NOTES.

DESCRIPTION
       Note: this function is obsolete.

       The IA-64-specific getunwind() system call copies the kernel's call frame
       unwind data into the buffer pointed to by buf and returns the size of the
       unwind data; this data describes the gate page (kernel code that is
       mapped into user space).

       The size of the buffer buf is specified in buf_size.  The data is copied
       only if buf_size is greater than or equal to the size of the unwind data
       and buf is not NULL; otherwise, no data is copied, and the call succeeds,
       returning the size that would be needed to store the unwind data.

       The first part of the unwind data contains an unwind table.  The rest
       contains the associated unwind information, in no particular order.  The
       unwind table contains entries of the following form:

           u64 start;      (64-bit address of start of function)
           u64 end;        (64-bit address of end of function)
           u64 info;       (BUF-relative offset to unwind info)

       An entry whose start value is zero indicates the end of the table.  For
       more information about the format, see the IA-64 Software Conventions and
       Runtime Architecture manual.

RETURN VALUE
       On success, getunwind() returns the size of the unwind data.  On error,
       -1 is returned and errno is set to indicate the error.

ERRORS
       getunwind() fails with the error EFAULT if the unwind info can't be
       stored in the space specified by buf.

VERSIONS
       This system call is available since Linux 2.4.

CONFORMING TO
       This system call is Linux-specific, and is available only on the IA-64
       architecture.

NOTES
       This system call has been deprecated.  The modern way to obtain the
       kernel's unwind data is via the vdso(7).

       Glibc does not provide a wrapper for this system call; in the unlikely
       event that you want to call it, use syscall(2).

SEE ALSO
       getauxval(3)

COLOPHON
       This page is part of release 5.10 of the Linux man-pages project.  A
       description of the project, information about reporting bugs, and the
       latest version of this page, can be found at
       https://www.kernel.org/doc/man-pages/.



Linux                              2017-09-15                       GETUNWIND(2)