1# warnings.m4 serial 11
2dnl Copyright (C) 2008-2016 Free Software Foundation, Inc.
3dnl This file is free software; the Free Software Foundation
4dnl gives unlimited permission to copy and/or distribute it,
5dnl with or without modifications, as long as this notice is preserved.
6
7dnl From Simon Josefsson
8
9# gl_AS_VAR_APPEND(VAR, VALUE)
10# ----------------------------
11# Provide the functionality of AS_VAR_APPEND if Autoconf does not have it.
12m4_ifdef([AS_VAR_APPEND],
13[m4_copy([AS_VAR_APPEND], [gl_AS_VAR_APPEND])],
14[m4_define([gl_AS_VAR_APPEND],
15[AS_VAR_SET([$1], [AS_VAR_GET([$1])$2])])])
16
17
18# gl_COMPILER_OPTION_IF(OPTION, [IF-SUPPORTED], [IF-NOT-SUPPORTED],
19#                       [PROGRAM = AC_LANG_PROGRAM()])
20# -----------------------------------------------------------------
21# Check if the compiler supports OPTION when compiling PROGRAM.
22#
23# FIXME: gl_Warn must be used unquoted until we can assume Autoconf
24# 2.64 or newer.
25AC_DEFUN([gl_COMPILER_OPTION_IF],
26[AS_VAR_PUSHDEF([gl_Warn], [gl_cv_warn_[]_AC_LANG_ABBREV[]_$1])dnl
27AS_VAR_PUSHDEF([gl_Flags], [_AC_LANG_PREFIX[]FLAGS])dnl
28AS_LITERAL_IF([$1],
29  [m4_pushdef([gl_Positive], m4_bpatsubst([$1], [^-Wno-], [-W]))],
30  [gl_positive="$1"
31case $gl_positive in
32  -Wno-*) gl_positive=-W`expr "X$gl_positive" : 'X-Wno-\(.*\)'` ;;
33esac
34m4_pushdef([gl_Positive], [$gl_positive])])dnl
35AC_CACHE_CHECK([whether _AC_LANG compiler handles $1], m4_defn([gl_Warn]), [
36  gl_save_compiler_FLAGS="$gl_Flags"
37  gl_AS_VAR_APPEND(m4_defn([gl_Flags]),
38    [" $gl_unknown_warnings_are_errors ]m4_defn([gl_Positive])["])
39  AC_LINK_IFELSE([m4_default([$4], [AC_LANG_PROGRAM([])])],
40                 [AS_VAR_SET(gl_Warn, [yes])],
41                 [AS_VAR_SET(gl_Warn, [no])])
42  gl_Flags="$gl_save_compiler_FLAGS"
43])
44AS_VAR_IF(gl_Warn, [yes], [$2], [$3])
45m4_popdef([gl_Positive])dnl
46AS_VAR_POPDEF([gl_Flags])dnl
47AS_VAR_POPDEF([gl_Warn])dnl
48])
49
50# gl_UNKNOWN_WARNINGS_ARE_ERRORS
51# ------------------------------
52# Clang doesn't complain about unknown warning options unless one also
53# specifies -Wunknown-warning-option -Werror.  Detect this.
54AC_DEFUN([gl_UNKNOWN_WARNINGS_ARE_ERRORS],
55[gl_COMPILER_OPTION_IF([-Werror -Wunknown-warning-option],
56   [gl_unknown_warnings_are_errors='-Wunknown-warning-option -Werror'],
57   [gl_unknown_warnings_are_errors=])])
58
59# gl_WARN_ADD(OPTION, [VARIABLE = WARN_CFLAGS],
60#             [PROGRAM = AC_LANG_PROGRAM()])
61# ---------------------------------------------
62# Adds parameter to WARN_CFLAGS if the compiler supports it when
63# compiling PROGRAM.  For example, gl_WARN_ADD([-Wparentheses]).
64#
65# If VARIABLE is a variable name, AC_SUBST it.
66AC_DEFUN([gl_WARN_ADD],
67[AC_REQUIRE([gl_UNKNOWN_WARNINGS_ARE_ERRORS])
68gl_COMPILER_OPTION_IF([$1],
69  [gl_AS_VAR_APPEND(m4_if([$2], [], [[WARN_CFLAGS]], [[$2]]), [" $1"])],
70  [],
71  [$3])
72m4_ifval([$2],
73         [AS_LITERAL_IF([$2], [AC_SUBST([$2])])],
74         [AC_SUBST([WARN_CFLAGS])])dnl
75])
76
77# Local Variables:
78# mode: autoconf
79# End:
80