xref: /freebsd/contrib/elftoolchain/libdwarf/dwarf_undef_macro.3 (revision ae500c1ff8974130f7f2692772cf288b90349e0d)

.\" Copyright (c) 2011 Kai Wang
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.\" $Id: dwarf_undef_macro.3 3644 2018-10-15 19:55:01Z jkoshy $
.\"
.Dd November 9, 2011
.Dt DWARF_UNDEF_MACRO 3
.Os
.Sh NAME
.Nm dwarf_undef_macro
.Nd record the removal of a macro definition
.Sh LIBRARY
.Lb libdwarf
.Sh SYNOPSIS
.In libdwarf.h
.Ft "int"
.Fo dwarf_undef_macro
.Fa "Dwarf_P_Debug dbg"
.Fa "Dwarf_Unsigned lineno"
.Fa "char *name"
.Fa "Dwarf_Error *err"
.Fc
.Sh DESCRIPTION
Function
.Fn dwarf_undef_macro
records the removal of a macro definition in a DWARF producer
instance.
.Pp
Argument
.Ar dbg
should reference a DWARF producer instance allocated using
.Xr dwarf_producer_init 3
or
.Xr dwarf_producer_init_b 3 .
.Pp
Argument
.Ar lineno
specifies the line number of the source line where the macro
definition was removed.
A value of zero indicates that the macro definition was removed before
any source files were read.
.Pp
Argument
.Ar name
should point to a NUL-terminated string containing the name
of the macro.
.Pp
If argument
.Ar err
is not NULL, it will be used to store error information in case of an
error.
.Sh RETURN VALUES
On success, function
.Fn dwarf_undef_macro
returns
.Dv DW_DLV_OK .
In case of an error, function
.Fn dwarf_undef_macro
returns
.Dv DW_DLV_ERROR
and sets the argument
.Ar err .
.Sh EXAMPLES
To record the fact that the macro named
.Dv _STDIO_H_
was removed at line 220 of the current macro file, use:
.Bd -literal -offset indent
Dwarf_P_Debug dbg;
Dwarf_Error de;

/* ... Assume 'dbg' refers to a DWARF producer instance... */
if (dwarf_undef_macro(dbg, 220, "_STDIO_H_", &de) != DW_DLV_OK)
	errx(EXIT_FAILURE, "dwarf_def_macro failed: %s",
	    dwarf_errmsg(-1));
.Ed
.Sh ERRORS
Function
.Fn dwarf_undef_macro
can fail with:
.Bl -tag -width ".Bq Er DW_DLE_ARGUMENT"
.It Bq Er DW_DLE_ARGUMENT
Either arguments
.Ar dbg
or
.Ar name
was NULL.
.It Bq Er DW_DLE_MEMORY
An out of memory condition was encountered during the execution of the
function.
.El
.Sh SEE ALSO
.Xr dwarf 3 ,
.Xr dwarf_def_macro 3 ,
.Xr dwarf_end_macro_file 3 ,
.Xr dwarf_producer_init 3 ,
.Xr dwarf_producer_init_b 3 ,
.Xr dwarf_start_macro_file 3 ,
.Xr dwarf_vendor_ext 3