1dnl Reentrant time functions: localtime_r, gmtime_r. 2 3dnl Copyright (C) 2003, 2006-2020 Free Software Foundation, Inc. 4dnl This file is free software; the Free Software Foundation 5dnl gives unlimited permission to copy and/or distribute it, 6dnl with or without modifications, as long as this notice is preserved. 7 8dnl Written by Paul Eggert. 9 10AC_DEFUN([gl_TIME_R], 11[ 12 dnl Persuade glibc and Solaris <time.h> to declare localtime_r. 13 AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS]) 14 15 AC_REQUIRE([gl_HEADER_TIME_H_DEFAULTS]) 16 AC_REQUIRE([AC_C_RESTRICT]) 17 18 dnl Some systems don't declare localtime_r() and gmtime_r() if _REENTRANT is 19 dnl not defined. 20 AC_CHECK_DECLS([localtime_r], [], [], 21 [[/* mingw's <time.h> provides the functions asctime_r, ctime_r, 22 gmtime_r, localtime_r only if <unistd.h> or <pthread.h> has 23 been included before. */ 24 #if defined __MINGW32__ 25 # include <unistd.h> 26 #endif 27 #include <time.h> 28 ]]) 29 if test $ac_cv_have_decl_localtime_r = no; then 30 HAVE_DECL_LOCALTIME_R=0 31 fi 32 33 AC_CHECK_FUNCS_ONCE([localtime_r]) 34 if test $ac_cv_func_localtime_r = yes; then 35 HAVE_LOCALTIME_R=1 36 AC_CACHE_CHECK([whether localtime_r is compatible with its POSIX signature], 37 [gl_cv_time_r_posix], 38 [AC_COMPILE_IFELSE( 39 [AC_LANG_PROGRAM( 40 [[/* mingw's <time.h> provides the functions asctime_r, ctime_r, 41 gmtime_r, localtime_r only if <unistd.h> or <pthread.h> has 42 been included before. */ 43 #if defined __MINGW32__ 44 # include <unistd.h> 45 #endif 46 #include <time.h> 47 ]], 48 [[/* We don't need to append 'restrict's to the argument types, 49 even though the POSIX signature has the 'restrict's, 50 since C99 says they can't affect type compatibility. */ 51 struct tm * (*ptr) (time_t const *, struct tm *) = localtime_r; 52 if (ptr) return 0; 53 /* Check the return type is a pointer. 54 On HP-UX 10 it is 'int'. */ 55 *localtime_r (0, 0);]]) 56 ], 57 [gl_cv_time_r_posix=yes], 58 [gl_cv_time_r_posix=no]) 59 ]) 60 if test $gl_cv_time_r_posix = yes; then 61 REPLACE_LOCALTIME_R=0 62 else 63 REPLACE_LOCALTIME_R=1 64 fi 65 else 66 HAVE_LOCALTIME_R=0 67 dnl On mingw, localtime_r() is defined as an inline function; use through a 68 dnl direct function call works but the use as a function pointer leads to a 69 dnl link error. 70 AC_CACHE_CHECK([whether localtime_r exists as an inline function], 71 [gl_cv_func_localtime_r_inline], 72 [AC_LINK_IFELSE( 73 [AC_LANG_PROGRAM( 74 [[/* mingw's <time.h> provides the functions asctime_r, ctime_r, 75 gmtime_r, localtime_r only if <unistd.h> or <pthread.h> has 76 been included before. */ 77 #if defined __MINGW32__ 78 # include <unistd.h> 79 #endif 80 #include <time.h> 81 ]], 82 [[time_t a; 83 struct tm r; 84 localtime_r (&a, &r); 85 ]]) 86 ], 87 [gl_cv_func_localtime_r_inline=yes], 88 [gl_cv_func_localtime_r_inline=no]) 89 ]) 90 if test $gl_cv_func_localtime_r_inline = yes; then 91 REPLACE_LOCALTIME_R=1 92 fi 93 fi 94]) 95 96# Prerequisites of lib/time_r.c. 97AC_DEFUN([gl_PREREQ_TIME_R], [ 98 : 99]) 100