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.\" Id: dwarf_srclines.3 3963 2022-03-12 16:07:32Z jkoshy
.\"
.Dd November 9, 2011
.Dt DWARF_SRCLINES 3
.Os
.Sh NAME
.Nm dwarf_srclines
.Nd retrieve line number information for a debugging information entry
.Sh LIBRARY
.Lb libdwarf
.Sh SYNOPSIS
.In libdwarf.h
.Ft int
.Fo dwarf_srclines
.Fa "Dwarf_Die die"
.Fa "Dwarf_Line **lines"
.Fa "Dwarf_Signed *nlines"
.Fa "Dwarf_Error *err"
.Fc
.Sh DESCRIPTION
Function
.Fn dwarf_srclines
returns line number information associated with a compilation unit.
Line number information is returned as an array of
.Vt Dwarf_Line
descriptors.
.Pp
Argument
.Fa die
should reference a DWARF debugging information entry descriptor
with line number information, see
.Xr dwarf 3 .
Argument
.Fa lines
should point to a location that will hold a pointer to the returned array
of
.Vt Dwarf_Line
descriptors.
Argument
.Fa nlines
should point to a location that will hold the number of descriptors
returned.
If argument
.Fa err
is not
.Dv NULL ,
it will be used to store error information in case of an error.
.Pp
The returned
.Vt Dwarf_Line
descriptors may be passed to the other line number functions in the
API set to retrieve specific information about each source line.
.Ss Memory Management
The memory area used for the array of
.Vt Dwarf_Line
descriptors returned in argument
.Fa lines
is owned by the
.Lb libdwarf .
The application should not attempt to free this pointer.
Portable code should instead use
.Fn dwarf_srclines_dealloc
to indicate that the memory may be freed.
.Sh RETURN VALUES
Function
.Fn dwarf_srclines
returns
.Dv DW_DLV_OK
when it succeeds.
In case of an error, it returns
.Dv DW_DLV_ERROR
and sets the argument
.Fa err .
.Sh EXAMPLES
To obtain an array of
.Vt Dwarf_Line
descriptors and to retrieve the source file, line number, and virtual address
associated with each descriptor:
.Bd -literal -offset indent
int n;
Dwarf_Die die;
Dwarf_Error de;
char *filename;
Dwarf_Line *lines;
Dwarf_Signed nlines;
Dwarf_Addr lineaddr;
Dwarf_Unsigned lineno;

/* variable "die" should reference a DIE for a compilation unit */

if (dwarf_srclines(die, &lines, &nlines, &de) != DW_DLV_OK)
	errx(EXIT_FAILURE, "dwarf_srclines: %s", dwarf_errmsg(de));

for (n = 0; n < nlines; n++) {
	/* Retrieve the file name for this descriptor. */
	if (dwarf_linesrc(lines[n], &filename, &de))
		errx(EXIT_FAILURE, "dwarf_linesrc: %s",
		    dwarf_errmsg(de));

	/* Retrieve the line number in the source file. */
	if (dwarf_lineno(lines[n], &lineno, &de))
		errx(EXIT_FAILURE, "dwarf_lineno: %s",
		    dwarf_errmsg(de));
	/* Retrieve the virtual address for this line. */
	if (dwarf_lineaddr(lines[n], &lineaddr, &de))
		errx(EXIT_FAILURE, "dwarf_lineaddr: %s",
		    dwarf_errmsg(de));
	}
.Ed
.Sh ERRORS
Function
.Fn dwarf_srclines
can fail with:
.Bl -tag -width ".Bq Er DW_DLE_ARGUMENT"
.It Bq Er DW_DLE_ARGUMENT
One of the arguments
.Fa die ,
.Fa lines
or
.Fa nlines
was
.Dv NULL .
.It Bq Er DW_DLE_NO_ENTRY
The compilation unit referenced by argument
.Fa die
does not have associated line number information.
.It Bq Er DW_DLE_MEMORY
An out of memory condition was encountered during the execution of
this function.
.El
.Sh SEE ALSO
.Xr dwarf 3 ,
.Xr dwarf_line_srcfileno 3 ,
.Xr dwarf_lineaddr 3 ,
.Xr dwarf_linebeginstatement 3 ,
.Xr dwarf_lineblock 3 ,
.Xr dwarf_lineendsequence 3 ,
.Xr dwarf_lineno 3 ,
.Xr dwarf_lineoff 3 ,
.Xr dwarf_linesrc 3 ,
.Xr dwarf_srcfiles 3 ,
.Xr dwarf_srclines_dealloc 3