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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       Note: this function is obsolete.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 associ-
       ated 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 unwind table.  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 gate DSO.  The address of the ELF header for this DSO is passed to  user  level
       via AT_SYSINFO_EHDR (see getauxval(3)).

       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 3.53 of the Linux man-pages project.  A  description  of  the
       project,     and    information	  about    reporting	bugs,	 can	be    found    at
       http://www.kernel.org/doc/man-pages/.

Linux					    2013-02-13				     GETUNWIND(2)
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