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+.\" Copyright (C) 2006 Red Hat, Inc. All Rights Reserved.
+.\" Written by Marcela Maslanova <mmaslano@redhat.com>
+.\" and Copyright 2013, Michael kerrisk <mtk.manpages@gmail.com>
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+.TH GETUNWIND 2 2013-02-13 Linux "Linux Programmer's Manual"
+.SH NAME
+getunwind \- copy the unwind data to caller's buffer
+.SH SYNOPSIS
+.nf
+.B #include <syscall.h>
+.B #include <linux/unwind.h>
+.sp
+.BI "long getunwind(void " *buf ", size_t " buf_size );
+.fi
+
+.IR Note :
+There is no glibc wrapper for this system call; see NOTES.
+.SH DESCRIPTION
+.I Note: this function is obsolete.
+
+The
+IA-64-specific
+.BR getunwind ()
+system call copies the kernel's call frame
+unwind data into the buffer pointed to by
+.I 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
+.I buf
+is specified in
+.IR buf_size .
+The data is copied only if
+.I buf_size
+is greater than or equal to the size of the unwind data and
+.I 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:
+
+.nf
+ 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)
+.fi
+
+An entry whose
+.I start
+value is zero indicates the end of the table.
+For more information about the format, see the
+.I IA-64 Software Conventions and Runtime Architecture
+manual.
+.SH RETURN VALUE
+On success,
+.BR getunwind ()
+returns the size of unwind table.
+On error, \-1 is returned and
+.I errno
+is set to indicate the error.
+.SH ERRORS
+.BR getunwind ()
+fails with the error
+.B EFAULT
+if the unwind info can't be stored in the space specified by
+.IR buf .
+.SH VERSIONS
+This system call is available since Linux 2.4.
+.SH CONFORMING TO
+This system call is Linux specific,
+and is available only on the IA-64 architecture.
+.SH NOTES
+This system call has been deprecated.
+The modern way to obtain the kernel's unwind data is via the gate DSO.
+The address of the ELF header for this DSO
+is passed to user level via
+.BR AT_SYSINFO_EHDR
+(see
+.BR getauxval (3)).
+
+Glibc does not provide a wrapper for this system call;
+in the unlikely event that you want to call it, use
+.BR syscall (2).
+.SH SEE ALSO
+.BR getauxval (3)
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