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      2 
      3 # Copyright (C) 2005-2007, 2009-2022 Free Software Foundation, Inc.
      4 #
      5 # This file is free software; the Free Software Foundation
      6 # gives unlimited permission to copy and/or distribute it,
      7 # with or without modifications, as long as this notice is preserved.
      8 
      9 dnl From Derek Price
     10 dnl
     11 dnl Provide getlogin_r when the system lacks it.
     12 dnl
     13 
     14 AC_DEFUN([gl_FUNC_GETLOGIN_R],
     15 [
     16   AC_REQUIRE([gl_UNISTD_H_DEFAULTS])
     17 
     18   dnl Persuade glibc <unistd.h> to declare getlogin_r().
     19   dnl Persuade Solaris <unistd.h> to provide the POSIX compliant declaration of
     20   dnl getlogin_r().
     21   AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
     22 
     23   AC_CHECK_DECLS_ONCE([getlogin_r])
     24   if test $ac_cv_have_decl_getlogin_r = no; then
     25     HAVE_DECL_GETLOGIN_R=0
     26   fi
     27 
     28   AC_CHECK_FUNCS_ONCE([getlogin_r])
     29   if test $ac_cv_func_getlogin_r = no; then
     30     HAVE_GETLOGIN_R=0
     31   else
     32     HAVE_GETLOGIN_R=1
     33     dnl On Mac OS X 10.13 and OSF/1 5.1, getlogin_r returns a truncated result
     34     dnl if the buffer is not large enough.
     35     AC_REQUIRE([AC_CANONICAL_HOST])
     36     AC_CACHE_CHECK([whether getlogin_r works with small buffers],
     37       [gl_cv_func_getlogin_r_works],
     38       [
     39         dnl Initial guess, used when cross-compiling.
     40 changequote(,)dnl
     41         case "$host_os" in
     42                           # Guess no on Mac OS X, OSF/1.
     43           darwin* | osf*) gl_cv_func_getlogin_r_works="guessing no" ;;
     44                           # Guess yes otherwise.
     45           *)              gl_cv_func_getlogin_r_works="guessing yes" ;;
     46         esac
     47 changequote([,])dnl
     48         AC_RUN_IFELSE(
     49           [AC_LANG_SOURCE([[
     50 #include <stddef.h>
     51 #include <string.h>
     52 #include <unistd.h>
     53 #if !HAVE_DECL_GETLOGIN_R
     54 extern
     55 # ifdef __cplusplus
     56 "C"
     57 # endif
     58 int getlogin_r (char *, size_t);
     59 #endif
     60 int
     61 main (void)
     62 {
     63   int result = 0;
     64   char buf[100];
     65 
     66   if (getlogin_r (buf, 0) == 0)
     67     result |= 1;
     68   if (getlogin_r (buf, 1) == 0)
     69     result |= 2;
     70   if (getlogin_r (buf, 100) == 0)
     71     {
     72       size_t n = strlen (buf);
     73       if (getlogin_r (buf, n) == 0)
     74         result |= 4;
     75     }
     76   return result;
     77 }]])],
     78           [gl_cv_func_getlogin_r_works=yes],
     79           [gl_cv_func_getlogin_r_works=no],
     80           [:])
     81       ])
     82     case "$gl_cv_func_getlogin_r_works" in
     83       *yes) ;;
     84       *) REPLACE_GETLOGIN_R=1 ;;
     85     esac
     86   fi
     87 ])
     88 
     89 AC_DEFUN([gl_PREREQ_GETLOGIN_R],
     90 [
     91   AC_CHECK_DECLS_ONCE([getlogin])
     92 ])
     93