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461 lines
12 KiB
Groff
461 lines
12 KiB
Groff
'\" t
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.\" Manual page created with latex2man on Wed Apr 20 14:03:33 PDT 2005
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.\" NOTE: This file is generated, DO NOT EDIT.
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.de Vb
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.ft CW
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.nf
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..
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.de Ve
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.ft R
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.fi
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..
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.TH "UNW\\_CREATE\\_ADDR\\_SPACE" "3" "20 April 2005" "Programming Library " "Programming Library "
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.SH NAME
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unw_create_addr_space
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\-\- create address space for remote unwinding
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.PP
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.SH SYNOPSIS
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.PP
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#include <libunwind.h>
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.br
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.PP
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unw_addr_space_t
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unw_create_addr_space(unw_accessors_t *ap,
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int
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byteorder);
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.br
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.PP
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.SH DESCRIPTION
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.PP
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The unw_create_addr_space()
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routine creates a new unwind
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address\-space and initializes it based on the call\-back routines
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passed via the ap
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pointer and the specified byteorder\&.
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The call\-back routines are described in detail below. The
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byteorder
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can be set to 0 to request the default byte\-order of
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the unwind target. To request a particular byte\-order,
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byteorder
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can be set to any constant defined by
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<endian.h>\&.
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In particular, __LITTLE_ENDIAN
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would
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request little\-endian byte\-order and __BIG_ENDIAN
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would
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request big\-endian byte\-order. Whether or not a particular byte\-order
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is supported depends on the target platform.
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.PP
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.SH CALL\-BACK ROUTINES
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.PP
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Libunwind
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uses a set of call\-back routines to access the
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information it needs to unwind a chain of stack\-frames. These
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routines are specified via the ap
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argument, which points to a
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variable of type unw_accessors_t\&.
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The contents of this
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variable is copied into the newly\-created address space, so the
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variable must remain valid only for the duration of the call to
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unw_create_addr_space().
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.PP
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The first argument to every call\-back routine is an address\-space
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identifier (as)
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and the last argument is an arbitrary,
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application\-specified void\-pointer (arg).
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When invoking a
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call\-back routine, libunwind
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sets the as
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argument to the
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address\-space on whose behalf the invocation is made and the arg
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argument to the value that was specified when
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unw_init_remote(3)
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was called.
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.PP
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The synopsis and a detailed description of every call\-back routine
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follows below.
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.PP
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.SS CALL\-BACK ROUTINE SYNOPSIS
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.PP
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int
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find_proc_info(unw_addr_space_t
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as,
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.br
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\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fPunw_word_t
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ip,
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unw_proc_info_t *pip,
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.br
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\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fPint
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need_unwind_info,
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void *arg);
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.br
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void
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put_unwind_info(unw_addr_space_t
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as,
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.br
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\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fPunw_proc_info_t *pip,
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void *arg);
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.br
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int
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get_dyn_info_list_addr(unw_addr_space_t
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as,
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.br
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\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fPunw_word_t *dilap,
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void *arg);
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.br
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int
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access_mem(unw_addr_space_t
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as,
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.br
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\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fPunw_word_t
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addr,
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unw_word_t *valp,
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.br
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\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fPint
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write,
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void *arg);
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.br
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int
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access_reg(unw_addr_space_t
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as,
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.br
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\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fPunw_regnum_t
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regnum,
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unw_word_t *valp,
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.br
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\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fPint
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write,
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void *arg);
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.br
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int
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access_fpreg(unw_addr_space_t
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as,
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.br
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\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fPunw_regnum_t
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regnum,
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unw_fpreg_t *fpvalp,
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.br
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\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fPint
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write,
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void *arg);
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.br
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int
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resume(unw_addr_space_t
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as,
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.br
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\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fPunw_cursor_t *cp,
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void *arg);
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.br
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int
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get_proc_name(unw_addr_space_t
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as,
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.br
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\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fPunw_word_t
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addr,
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char *bufp,
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.br
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\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fPsize_t
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buf_len,
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unw_word_t *offp,
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.br
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\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fP\fB \fPvoid *arg);
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.br
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.PP
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.SS FIND_PROC_INFO
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.PP
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Libunwind
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invokes the find_proc_info()
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call\-back to
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locate the information need to unwind a particular procedure. The
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ip
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argument is an instruction\-address inside the procedure whose
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information is needed. The pip
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argument is a pointer to the
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variable used to return the desired information. The type of this
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variable is unw_proc_info_t\&.
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See
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unw_get_proc_info(3)
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for details. Argument
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need_unwind_info
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is zero if the call\-back does not need to
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provide values for the following members in the
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unw_proc_info_t
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structure: format,
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unwind_info_size,
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and unwind_info\&.
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If
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need_unwind_info
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is non\-zero, valid values need to be returned
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in these members. Furthermore, the contents of the memory addressed
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by the unwind_info
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member must remain valid until the info is
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released via the put_unwind_info
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call\-back (see below).
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.PP
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On successful completion, the find_proc_info()
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call\-back must
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return zero. Otherwise, the negative value of one of the
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unw_error_t
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error\-codes may be returned. In particular, this
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call\-back may return \-UNW_ESTOPUNWIND
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to signal the end of
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the frame\-chain.
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.PP
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.SS PUT_UNWIND_INFO
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.PP
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Libunwind
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invokes the put_unwind_info()
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call\-back to
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release the resources (such as memory) allocated by a previous call to
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find_proc_info()
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with the need_unwind_info
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argument
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set to a non\-zero value. The pip
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argument has the same value as
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the argument of the same name in the previous matching call to
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find_proc_info().
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Note that libunwind
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does \fInot\fP
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invoke put_unwind_info
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for calls to find_proc_info()
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with a zero need_unwind_info
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argument.
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.PP
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.SS GET_DYN_INFO_LIST_ADDR
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.PP
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Libunwind
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invokes the get_dyn_info_list_addr()
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call\-back to obtain the address of the head of the dynamic unwind\-info
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registration list. The variable stored at the returned address must
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have a type of unw_dyn_info_list_t
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(see
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_U_dyn_register(3)).
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The dliap
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argument is a pointer
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to a variable of type unw_word_t
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which is used to return the
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address of the dynamic unwind\-info registration list. If no dynamic
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unwind\-info registration list exist, the value pointed to by
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dliap
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must be cleared to zero. Libunwind
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will cache the
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value returned by get_dyn_info_list_addr()
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if caching is
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enabled for the given address\-space. The cache can be cleared with a
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call to unw_flush_cache().
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.PP
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On successful completion, the get_dyn_info_list_addr()
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call\-back must return zero. Otherwise, the negative value of one of
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the unw_error_t
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error\-codes may be returned.
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.PP
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.SS ACCESS_MEM
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.PP
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Libunwind
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invokes the access_mem()
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call\-back to read
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from or write to a word of memory in the target address\-space. The
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address of the word to be accessed is passed in argument addr\&.
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To read memory, libunwind
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sets argument write
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to zero and
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valp
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to point to the word that receives the read value. To
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write memory, libunwind
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sets argument write
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to a non\-zero
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value and valp
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to point to the word that contains the value to
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be written. The word that valp
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points to is always in the
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byte\-order of the host\-platform, regardless of the byte\-order of the
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target. In other words, it is the responsibility of the call\-back
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routine to convert between the target\&'s and the host\&'s byte\-order, if
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necessary.
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.PP
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On successful completion, the access_mem()
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call\-back must return zero. Otherwise, the negative value of one of
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the unw_error_t
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error\-codes may be returned.
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.PP
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.SS ACCESS_REG
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.PP
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Libunwind
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invokes the access_reg()
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call\-back to read
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from or write to a scalar (non\-floating\-point) CPU register. The
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index of the register to be accessed is passed in argument
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regnum\&.
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To read a register, libunwind
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sets argument
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write
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to zero and valp
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to point to the word that receives
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the read value. To write a register, libunwind
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sets argument
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write
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to a non\-zero value and valp
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to point to the word
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that contains the value to be written. The word that valp
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points to is always in the byte\-order of the host\-platform, regardless
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of the byte\-order of the target. In other words, it is the
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responsibility of the call\-back routine to convert between the
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target\&'s and the host\&'s byte\-order, if necessary.
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.PP
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On successful completion, the access_reg()
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call\-back must
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return zero. Otherwise, the negative value of one of the
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unw_error_t
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error\-codes may be returned.
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.PP
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.SS ACCESS_FPREG
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.PP
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Libunwind
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invokes the access_fpreg()
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call\-back to read
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from or write to a floating\-point CPU register. The index of the
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register to be accessed is passed in argument regnum\&.
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To read a
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register, libunwind
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sets argument write
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to zero and
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fpvalp
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to point to a variable of type unw_fpreg_t
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that
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receives the read value. To write a register, libunwind
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sets
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argument write
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to a non\-zero value and fpvalp
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to point to
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the variable of type unw_fpreg_t
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that contains the value to
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be written. The word that fpvalp
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points to is always in the
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byte\-order of the host\-platform, regardless of the byte\-order of the
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target. In other words, it is the responsibility of the call\-back
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routine to convert between the target\&'s and the host\&'s byte\-order, if
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necessary.
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.PP
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On successful completion, the access_fpreg()
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call\-back must
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return zero. Otherwise, the negative value of one of the
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unw_error_t
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error\-codes may be returned.
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.PP
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.SS RESUME
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.PP
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Libunwind
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invokes the resume()
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call\-back to resume
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execution in the target address space. Argument cp
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is the
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unwind\-cursor that identifies the stack\-frame in which execution
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should resume. By the time libunwind
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invokes the resume
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call\-back, it has already established the desired machine\- and
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memory\-state via calls to the access_reg(),
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access_fpreg,
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and access_mem()
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call\-backs. Thus, all
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the call\-back needs to do is perform whatever action is needed to
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actually resume execution.
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.PP
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The resume
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call\-back is invoked only in response to a call to
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unw_resume(3),
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so applications which never invoke
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unw_resume(3)
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need not define the resume
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callback.
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.PP
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On successful completion, the resume()
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call\-back must return
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zero. Otherwise, the negative value of one of the
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unw_error_t
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error\-codes may be returned. As a special case,
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when resuming execution in the local address space, the call\-back will
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not return on success.
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.PP
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.SS GET_PROC_NAME
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.PP
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Libunwind
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invokes the get_proc_name()
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call\-back to
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obtain the procedure\-name of a static (not dynamically generated)
|
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procedure. Argument addr
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is an instruction\-address within the
|
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procedure whose name is to be obtained. The bufp
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argument is a
|
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pointer to a character\-buffer used to return the procedure name. The
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size of this buffer is specified in argument buf_len\&.
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The
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returned name must be terminated by a NUL character. If the
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procedure\&'s name is longer than buf_len
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bytes, it must be
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|
truncated to buf_len\-1
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bytes, with the last byte in the
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buffer set to the NUL character and \-UNW_ENOMEM
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must be
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returned. Argument offp
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is a pointer to a word which is used to
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return the byte\-offset relative to the start of the procedure whose
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name is being returned. For example, if procedure foo()
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starts
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at address 0x40003000, then invoking get_proc_name()
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with
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addr
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set to 0x40003080 should return a value of 0x80 in the word
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pointed to by offp
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(assuming the procedure is at least 0x80
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bytes long).
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.PP
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|
On successful completion, the get_proc_name()
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call\-back must
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return zero. Otherwise, the negative value of one of the
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unw_error_t
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error\-codes may be returned.
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.PP
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|
.SH RETURN VALUE
|
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|
.PP
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|
On successful completion, unw_create_addr_space()
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|
returns a
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non\-NULL
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value that represents the newly created
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address\-space. Otherwise, NULL
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is returned.
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|
.PP
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|
.SH THREAD AND SIGNAL SAFETY
|
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|
.PP
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|
unw_create_addr_space()
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is thread\-safe but \fInot\fP
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|
safe to use from a signal handler.
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.PP
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|
.SH SEE ALSO
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|
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|
.PP
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|
_U_dyn_register(3),
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libunwind(3),
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unw_destroy_addr_space(3),
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unw_get_proc_info(3),
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unw_init_remote(3),
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unw_resume(3)
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.PP
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.SH AUTHOR
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.PP
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|
David Mosberger\-Tang
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.br
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Hewlett\-Packard Labs
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.br
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Palo\-Alto, CA 94304
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.br
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Email: \fBdavidm@hpl.hp.com\fP
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.br
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WWW: \fBhttp://www.hpl.hp.com/research/linux/libunwind/\fP\&.
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.\" NOTE: This file is generated, DO NOT EDIT.
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