1 # asm-underscore.m4 serial 2
2 dnl Copyright (C) 2010-2012 Free Software Foundation, Inc.
3 dnl This file is free software; the Free Software Foundation
4 dnl gives unlimited permission to copy and/or distribute it,
5 dnl with or without modifications, as long as this notice is preserved.
7 dnl From Bruno Haible. Based on as-underscore.m4 in GNU clisp.
10 # Tests for the prefix of C symbols at the assembly language level and the
11 # linker level. This prefix is either an underscore or empty. Defines the
12 # C macro USER_LABEL_PREFIX to this prefix, and sets ASM_SYMBOL_PREFIX to
13 # a stringified variant of this prefix.
15 AC_DEFUN([gl_ASM_SYMBOL_PREFIX],
17 dnl We don't use GCC's __USER_LABEL_PREFIX__ here, because
18 dnl 1. It works only for GCC.
19 dnl 2. It is incorrectly defined on some platforms, in some GCC versions.
20 AC_REQUIRE([gl_C_ASM])
22 [whether C symbols are prefixed with underscore at the linker level],
23 [gl_cv_prog_as_underscore],
24 [cat > conftest.c <<EOF
26 extern "C" int foo (void);
28 int foo(void) { return 0; }
30 # Look for the assembly language name in the .s file.
31 AC_TRY_COMMAND(${CC-cc} $CFLAGS $CPPFLAGS $gl_c_asm_opt conftest.c) >/dev/null 2>&1
32 if grep _foo conftest.$gl_asmext >/dev/null ; then
33 gl_cv_prog_as_underscore=yes
35 gl_cv_prog_as_underscore=no
39 if test $gl_cv_prog_as_underscore = yes; then
44 AC_DEFINE_UNQUOTED([USER_LABEL_PREFIX], [$USER_LABEL_PREFIX],
45 [Define to the prefix of C symbols at the assembler and linker level,
46 either an underscore or empty.])
47 ASM_SYMBOL_PREFIX='"'${USER_LABEL_PREFIX}'"'
48 AC_SUBST([ASM_SYMBOL_PREFIX])
52 # Determines how to produce an assembly language file from C source code.
54 # gl_asmext - the extension of assembly language output,
55 # gl_c_asm_opt - the C compiler option that produces assembly language output.
59 AC_EGREP_CPP([MicrosoftCompiler],