---
name: "dwarf_get_macro_details"
section: "3"
platform: "freebsd"
package: "base"
version: "16.0-CURRENT-20261027-61c70dc16a79"
release: "FreeBSD 16.0-CURRENT (2026-10-27)"
platforms: ["freebsd"]
url: "https://new.carta.tech/dwarf_get_macro_details"
---

# dwarf\_get\_macro\_details(3)

retrieve macro information

## NAME

**dwarf\_get\_macro\_details** – retrieve macro information

## LIBRARY

library “libdwarf”

## SYNOPSIS

**#include \<libdwarf.h\>**

*int*\

**dwarf\_get\_macro\_details**(*Dwarf\_Debug dbg*, *Dwarf\_Off offset*, *Dwarf\_Unsigned max\_count*, *Dwarf\_Signed \*entry\_cnt*, *Dwarf\_Macro\_Details \*\*details*, *Dwarf\_Error \*err*);

## DESCRIPTION

Function **dwarf\_get\_macro\_details**() retrieves information about macros associated with a DWARF debug context. Information about macro entries are returned as an array of descriptors of type *Dwarf\_Macro\_Details*, with each *Dwarf\_Macro\_Details* descriptor describing one macro information entry.

Argument *dbg* should reference a DWARF debug context allocated using [dwarf\_init(3)](/dwarf_init/3.md). Argument *offset* is an offset, relative to the “.debug\_macinfo” section, to the start of the desired macro information. Argument *max\_count* specifies the maximum number of macro information entries to be returned, or 0 if all entries are to be returned. Argument *entry\_cnt* should point to a location that will be set to the number of entries actually returned. Argument *details* should point to a location that will be set to a pointer to an array of *Dwarf\_Macro\_Details* descriptors. If argument *err* is not NULL, it will be used to store error information in case of an error.

*Dwarf\_Macro\_Details* descriptors are defined in the header file ⟨libdwarf.h⟩, and consist of the following fields:

- *dmd\_offset*

  The section-relative offset within the “.debug\_macinfo” section of the macro information entry being described.

- *dmd\_type*

  The type code of this macro information entry; one of the DW\_MACINFO\_\* constants defined by the DWARF specification.

- *dmd\_lineno*

  The line number associated with the macro information entry, or 0 if there is no applicable line number.

- *dmd\_fileindex*

  The source file index for the macro information entry. This field is only meaningful when *dmd\_type* field is set to DW\_MACINFO\_start\_file.

- *dmd\_macro*

  The contents of this field is a pointer to a NUL-terminated string whose meaning depends on the value of the *dmd\_type* field:

  - DW\_MACINFO\_define

    The returned string contains the macro name and value.

  - DW\_MACINFO\_undef

    The string holds the macro name.

  - DW\_MACINFO\_vendor\_ext

    The *dmd\_macro* field points to a vendor defined string.

    The field is NULL for other values of *dmd\_type*.

### Memory Management

The memory area used for the array of *Dwarf\_Macro\_Details* descriptors returned in argument *details* is owned by the library “libdwarf”. The application should not attempt to directly free this pointer. Portable code should instead use **dwarf\_dealloc**() with the allocation type DW\_DLA\_STRING to indicate that the memory may be freed.

## RETURN VALUES

Function **dwarf\_get\_macro\_details**() returns DW\_DLV\_OK when it succeeds. It returns DW\_DLV\_NO\_ENTRY if there is no more macro information at the specified offset *offset*. In case of an error, it returns DW\_DLV\_ERROR and sets the argument *err*.

## EXAMPLES

To loop through all the macro information entries associated with a DWARF debug context:

```
Dwarf_Debug dbg;
Dwarf_Unsigned offset;
Dwarf_Signed cnt;
Dwarf_Macro_Details *md;
Dwarf_Error de;
offset = 0;
while (dwarf_get_macro_details(dbg, offset, 0,
    &cnt, &md, &de) == DW_DLV_OK) {
	for (i = 0; i < cnt; i++) {
		/* Access fields of md[i] ... */
	}
	offset = md[cnt - 1].dmd_offset + 1;
}
```

## ERRORS

Function **dwarf\_get\_macro\_details**() can fail with:

- \[DW\_DLE\_ARGUMENT\]

  One of the arguments *dbg*, *entry\_cnt* or *details* was NULL.

- \[DW\_DLE\_NO\_ENTRY\]

  There is no more macro information at the specified offset *offset*.

## SEE ALSO

[dwarf(3)](/dwarf/3.md), [dwarf\_dealloc(3)](/dwarf_dealloc/3.md), [dwarf\_find\_macro\_value\_start(3)](/dwarf_find_macro_value_start/3.md), [dwarf\_init(3)](/dwarf_init/3.md)