# Configure a replacement for <strings.h>.
# serial 9

# Copyright (C) 2007, 2009-2021 Free Software Foundation, Inc.
# This file is free software; the Free Software Foundation
# gives unlimited permission to copy and/or distribute it,
# with or without modifications, as long as this notice is preserved.

AC_DEFUN_ONCE([gl_STRINGS_H],
[
  dnl Ensure to expand the default settings once only, before all statements
  dnl that occur in other macros.
  AC_REQUIRE([gl_STRINGS_H_DEFAULTS])

  gl_CHECK_NEXT_HEADERS([strings.h])
  if test $ac_cv_header_strings_h = yes; then
    HAVE_STRINGS_H=1
  else
    HAVE_STRINGS_H=0
  fi
  AC_SUBST([HAVE_STRINGS_H])

  dnl Check for declarations of anything we want to poison if the
  dnl corresponding gnulib module is not in use.
  gl_WARN_ON_USE_PREPARE([[
    /* Minix 3.1.8 has a bug: <sys/types.h> must be included before
       <strings.h>.  */
    #include <sys/types.h>
    #include <strings.h>
    ]], [ffs strcasecmp strncasecmp])
])

# gl_STRINGS_MODULE_INDICATOR([modulename])
# sets the shell variable that indicates the presence of the given module
# to a C preprocessor expression that will evaluate to 1.
# This macro invocation must not occur in macros that are AC_REQUIREd.
AC_DEFUN([gl_STRINGS_MODULE_INDICATOR],
[
  dnl Ensure to expand the default settings once only.
  gl_STRINGS_H_REQUIRE_DEFAULTS
  gl_MODULE_INDICATOR_SET_VARIABLE([$1])
])

# Initializes the default values for AC_SUBSTed shell variables.
# This macro must not be AC_REQUIREd.  It must only be invoked, and only
# outside of macros or in macros that are not AC_REQUIREd.
AC_DEFUN([gl_STRINGS_H_REQUIRE_DEFAULTS],
[
  m4_defun(GL_MODULE_INDICATOR_PREFIX[_STRINGS_H_MODULE_INDICATOR_DEFAULTS], [
    gl_MODULE_INDICATOR_INIT_VARIABLE([GNULIB_FFS])
  ])
  m4_require(GL_MODULE_INDICATOR_PREFIX[_STRINGS_H_MODULE_INDICATOR_DEFAULTS])
  AC_REQUIRE([gl_STRINGS_H_DEFAULTS])
])

AC_DEFUN([gl_STRINGS_H_DEFAULTS],
[
  dnl Assume proper GNU behavior unless another module says otherwise.
  HAVE_FFS=1;              AC_SUBST([HAVE_FFS])
  HAVE_STRCASECMP=1;       AC_SUBST([HAVE_STRCASECMP])
  HAVE_DECL_STRNCASECMP=1; AC_SUBST([HAVE_DECL_STRNCASECMP])
])
