DWARF_GET_FDE_INFO_FOR_CFA_REGS3(3) | Library Functions Manual | DWARF_GET_FDE_INFO_FOR_CFA_REGS3(3)

# NAME

`dwarf_get_fde_info_for_cfa_regs3` —
retrieve a CFA register rule

# LIBRARY

DWARF Access Library (libdwarf, -ldwarf)

# SYNOPSIS

`#include <libdwarf.h>`

int
`dwarf_get_fde_info_for_cfa_regs3`(Dwarf_Fde fde, Dwarf_Addr pc, Dwarf_Small *type, Dwarf_Signed *offset_relevant, Dwarf_Signed *register_num, Dwarf_Signed *offset_or_block_len, Dwarf_Ptr *block_ptr, Dwarf_Addr *row_pc, Dwarf_Error *err);

# DESCRIPTION

Function `dwarf_get_fde_info_for_cfa_reg3`() retrieves the CFA register rule for a given program counter address from the register rule table associated with an FDE descriptor.

Argument fde should reference a valid DWARF FDE descriptor.

Argument pc should hold the program counter address to be used to locate the desired register rule row.

On successful execution, `dwarf_get_fde_info_for_cfa_reg3`() stores information about the CFA register rule found into the locations pointed to by the arguments type, offset_relevant, register_num, offset_or_block_len, block_ptr and row_pc.

Argument type should point to a location which will hold the type code of the register rule found. The returned value is one of the `DW_EXPR_*` contants defined in the header file `<libdwarf.h>`.

If there is an offset value associated with the CFA register rule, the location pointed to by argument offset_relevant will be set to 1.

Argument register_num should point to a location which will hold the register number associated with the CFA register rule.

If the CFA register rule is of type `DW_EXPR_OFFSET` or `DW_EXPR_VAL_OFFSET`, the location pointed to by argument offset_or_block_len will be set to the offset value associated with the register rule, or to 0 if the register rule does not have an offset value. If the type code is `DW_EXPR_EXPRESSION` or `DW_EXPR_VAL_EXPRESSION`, the location pointed to by argument offset_or_block_len will be set to the length in bytes of the DWARF expression block associated with the register rule.

Argument block_ptr should point to a location which will be set to a pointer to the content of the DWARF expression block associated with the CFA register rule.

Argument row_pc should point to a location which will be set to the lowest program counter address associated with the register rule found.

If argument err is not NULL, it will be used to return an error descriptor in case of an error.

# RETURN VALUES

Function `dwarf_get_fde_info_for_cfa_reg3`() returns `DW_DLV_OK` when it succeeds. In case of an error, it returns `DW_DLV_ERROR` and sets the argument err.

# ERRORS

Function `dwarf_get_fde_info_for_cfa_reg3`() can fail with:

[`DW_DLE_ARGUMENT`]
  One of the arguments block_ptr, fde, offset_or_block_len, offset_relevant, register_num, row_pc, or type was NULL.
[`DW_DLE_PC_NOT_IN_FDE_RANGE`]
  The program counter value provided in argument pc did not fall in the range covered by argument fde.

# SEE ALSO

dwarf(3), dwarf_get_fde_at_pc(3), dwarf_get_fde_info_for_all_regs(3), dwarf_get_fde_info_for_all_regs3(3), dwarf_get_fde_info_for_reg(3), dwarf_get_fde_info_for_reg3(3), dwarf_get_fde_n(3), dwarf_set_frame_cfa_value(3), dwarf_set_frame_rule_table_size(3), dwarf_set_frame_rule_initial_value(3), dwarf_set_frame_same_value(3), dwarf_set_frame_undefined_value(3)

June 12, 2011 | NetBSD 9.2