Training courses

Kernel and Embedded Linux

Bootlin training courses

Embedded Linux, kernel,
Yocto Project, Buildroot, real-time,
graphics, boot time, debugging...

Bootlin logo

Elixir Cross Referencer

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
#							-*- Autotest -*-

AT_BANNER([Semantics.])

# Copyright (C) 2000-2002, 2004-2007, 2009-2012 Free Software
# Foundation, Inc.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.


## -------------------------------- ##
## Members of the AC_CHECK family.  ##
## -------------------------------- ##


# AC_CHECK_LIB
# ------------
# Well, I can't imagine a system where `cos' is neither in libc, nor
# in libm.  Nor can I imagine a lib more likely to exists than libm.
# But there are systems without libm, on which we don't want to have
# this test fail, so exit successfully if `cos' is in libc.
AT_CHECK_MACRO([AC_CHECK_LIB],
[AC_TRY_LINK_FUNC(cos,
		  [AC_MSG_ERROR([`cos' is in `libc'], 77)])

AC_CHECK_LIB(m, cos,,
	     [AC_MSG_ERROR([cannot find `cos' in `libm'])])

# No kidding, using variables was broken in 2.50 :(
ac_sin=sin
AC_CHECK_LIB(m, $ac_sin,,
      [AC_MSG_ERROR([cannot find `\$ac_sin' (= `$ac_sin') in `libm'])])

ac_m=m
AC_CHECK_LIB($ac_m, acos,,
      [AC_MSG_ERROR([cannot find `acos' in `\$ac_m' (= `$ac_m')])])

ac_asin=asin
AC_CHECK_LIB($ac_m, $ac_asin,,
      [AC_MSG_ERROR([cannot find `\$ac_asin' (= `$ac_asin') in `\$ac_m' (= `$ac_m')])])

# But if the bug is in the caching mechanism, then be sure we
# correctly detect failures.

AC_CHECK_LIB(m, cossack,
	     [AC_MSG_ERROR([found `cossack' in `libm'])])

# No kidding, using variables was broken in 2.50 :(
ac_sinner=sinner
AC_CHECK_LIB(m, $ac_sinner,
      [AC_MSG_ERROR([found `\$ac_sinner' (= `$ac_sinner') in `libm'])])

ac_m=m
AC_CHECK_LIB($ac_m, acossack,
      [AC_MSG_ERROR([found `acossack' in `\$ac_m' (= `$ac_m')])])

ac_asinner=asinner
AC_CHECK_LIB($ac_m, $ac_asinner,
      [AC_MSG_ERROR([found `\$ac_asinner' (= `$ac_asinner') in `\$ac_m' (= `$ac_m')])])

])


# AC_SEARCH_LIBS
# --------------
AT_CHECK_MACRO([AC_SEARCH_LIBS],
[
AC_SEARCH_LIBS(cos, oser m ust,,
	     [AC_MSG_ERROR([cannot find `cos'])])

case "$ac_cv_search_cos" in
  -loser|-lust) AC_MSG_ERROR([jeez, $ac_cv_search_cos must be a cool library!]) ;;
esac
])


# AC_SEARCH_LIBS (none needed)
# ----------------------------
AT_CHECK_MACRO([AC_SEARCH_LIBS (none needed)],
[
AC_SEARCH_LIBS(printf, oser c ust,,
	     [AC_MSG_ERROR([cannot find `printf'])])

case "$ac_cv_search_printf" in
  -loser|-lust) AC_MSG_ERROR([jeez, $ac_cv_search_printf must be a cool library!]) ;;
  -lc) AC_MSG_ERROR([huh, you need to give -lc?])
esac
])


# AC_CHECK_DECLS
# --------------
# Check that it performs the correct actions:
AT_CHECK_MACRO([AC_CHECK_DECLS],
[[AC_CHECK_DECLS([yes, no, myenum, mystruct, myfunc, mymacro1, mymacro2],,,
		 [[int yes = 1;
		   enum { myenum };
		   struct { int x[20]; } mystruct;
		   extern int myfunc();
		   #define mymacro1(arg) arg
		   #define mymacro2]])
  # The difference in space-before-open-paren is intentional.
  AC_CHECK_DECLS([basenam (char *), dirnam(char *),
		  [moreargs (char, short, int, long, void *, char [], float, double)]],,,
		 [[#ifdef __cplusplus
		   extern "C++" char *basenam (char *);
		   extern "C++" const char *basenam (const char *);
		   #else
		   extern char *basenam (const char *);
		   #endif
		   #ifdef __cplusplus
		   extern "C" {
		   #endif
		   extern int moreargs (char, short, int, long, void *,
					char [], float, double);
		   #ifdef __cplusplus
		   }
		   #endif
		   ]])
  AC_CHECK_DECL([declared (char *)],, [AS_EXIT([1])],
		[[#ifdef __cplusplus
		  extern "C++" char *declared (char *);
		  extern "C++" const char *declared (const char *);
		  #else
		  extern char *declared (const char *);
		  #endif
		]])
  AC_CHECK_DECL([undeclared (char *)], [AS_EXIT([1])],, [[]])
]],
[AT_CHECK_DEFINES(
[#define HAVE_DECL_BASENAM 1
#define HAVE_DECL_DIRNAM 0
#define HAVE_DECL_MOREARGS 1
#define HAVE_DECL_MYENUM 1
#define HAVE_DECL_MYFUNC 1
#define HAVE_DECL_MYMACRO1 1
#define HAVE_DECL_MYMACRO2 1
#define HAVE_DECL_MYSTRUCT 1
#define HAVE_DECL_NO 0
#define HAVE_DECL_YES 1
])])


# AC_CHECK_FUNCS
# --------------
# Check that it performs the correct actions:
# Must define HAVE_PRINTF, but not HAVE_AUTOCONF_FTNIRP
AT_CHECK_MACRO([AC_CHECK_FUNCS],
[AC_CHECK_FUNCS(printf autoconf_ftnirp)],
[AT_CHECK_DEFINES(
[/* #undef HAVE_AUTOCONF_FTNIRP */
#define HAVE_PRINTF 1
])])


# AC_REPLACE_FUNCS
# ----------------
# Check that it performs the correct actions: autoconf_ftnirp.c must
# be compiled, and must define HAVE_PRINTF, but not HAVE_AUTOCONF_FTNIRP
# FIXME: Maybe check the traces?
AT_SETUP([AC_REPLACE_FUNCS])

AT_DATA([config.in],
[@LIBOBJS@
])

AT_CONFIGURE_AC(
[AC_CONFIG_FILES([config.libobjs:config.in])
AC_REPLACE_FUNCS([printf \
autoconf_ftnirp])
funcs='fprintf fopen autoconf_ftnirpf'
AH_TEMPLATE([HAVE_FOPEN], [])
AH_TEMPLATE([HAVE_FPRINTF], [])
AH_TEMPLATE([HAVE_AUTOCONF_FTNIRPF], [])
AC_REPLACE_FUNCS([\
$funcs])
AS_UNSET([funcs])])

AT_CHECK_AUTOCONF([-W obsolete])
AT_CHECK_AUTOHEADER
AT_CHECK_CONFIGURE
AT_CHECK_ENV
AT_CHECK_DEFINES(
[/* #undef HAVE_AUTOCONF_FTNIRP */
/* #undef HAVE_AUTOCONF_FTNIRPF */
#define HAVE_FOPEN 1
#define HAVE_FPRINTF 1
#define HAVE_PRINTF 1
])

AT_CHECK([sed 's/  */ /g;s/^ //;s/ $//' config.libobjs], [],
	 [${LIBOBJDIR}autoconf_ftnirp$U.o ${LIBOBJDIR}autoconf_ftnirpf$U.o
])

AT_CLEANUP


# AC_CHECK_HEADERS
# ----------------
# Check that it performs the correct actions:
# Must define HAVE_STDIO_H, but not HAVE_AUTOCONF_IO_H.
AT_SETUP([AC_CHECK_HEADERS])

AT_DATA([autoconf_io.h],
[blah blah
])

AT_CONFIGURE_AC([AC_CHECK_HEADERS(stdio.h autoconf_io.h)])
AT_CHECK_AUTOCONF([-W obsolete])
AT_CHECK_AUTOHEADER
AT_CHECK_CONFIGURE([CPPFLAGS=-I.], [0], [ignore],
[configure: WARNING: autoconf_io.h: present but cannot be compiled
configure: WARNING: autoconf_io.h:     check for missing prerequisite headers?
configure: WARNING: autoconf_io.h: see the Autoconf documentation
configure: WARNING: autoconf_io.h:     section "Present But Cannot Be Compiled"
configure: WARNING: autoconf_io.h: proceeding with the compiler's result
])
AT_CHECK_ENV
AT_CHECK_DEFINES(
[/* #undef HAVE_AUTOCONF_IO_H */
#define HAVE_STDIO_H 1
])

AT_CLEANUP


# AC_CHECK_HEADERS_OLD
# --------------------
# Check that it performs the correct actions:
# Must not check prerequisites, hence define header2.h
AT_SETUP([AC_CHECK_HEADERS (preprocessor test)])

AT_DATA([header1.h],
[typedef int foo;
])

AT_DATA([header2.h],
[typedef foo bar;
])

AT_CONFIGURE_AC([AC_CHECK_HEADERS(header2.h, [], [], -)])

AT_CHECK_AUTOCONF([-W obsolete])
AT_CHECK_AUTOHEADER
AT_CHECK_CONFIGURE([CPPFLAGS=-I.])
AT_CHECK_ENV
AT_CHECK_DEFINES(
[#define HAVE_HEADER2_H 1
])

AT_CLEANUP


# AC_CHECK_HEADERS_NEW
# --------------------
# Check that it performs the correct actions:
# Must check prerequisites, hence define header2.h but not header3.h
AT_SETUP([AC_CHECK_HEADERS (compiler test)])

AT_DATA([header1.h],
[typedef int foo;
])

AT_DATA([header2.h],
[typedef foo bar;
])

AT_DATA([header3.h],
[typedef bar wow;
])

AT_CONFIGURE_AC(
[AC_CHECK_HEADERS(header2.h header3.h, [], [], [[@%:@include "header1.h"]])])

AT_CHECK_AUTOCONF([-W obsolete])
AT_CHECK_AUTOHEADER
AT_CHECK_CONFIGURE([CPPFLAGS=-I.])
AT_CHECK_ENV
AT_CHECK_DEFINES(
[#define HAVE_HEADER2_H 1
/* #undef HAVE_HEADER3_H */
])

AT_CLEANUP


# AC_CHECK_MEMBER
# ---------------
# Check that it performs the correct actions.
# Must define HAVE_STRUCT_YES_S_YES, but not HAVE_STRUCT_YES_S_NO.
AT_CHECK_MACRO([AC_CHECK_MEMBER],
[[AC_CHECK_MEMBER([struct yes_s.yes],
		  [AC_DEFINE([HAVE_STRUCT_YES_S_YES], [1],
			     [Define to 1 if `yes' is a member of `struct yes_s'.])],,
		   [struct sub { int x; };
		    struct yes_s { int yes; struct sub substruct; };])
  AC_CHECK_MEMBER([struct yes_s.no],
		  [AC_DEFINE([HAVE_STRUCT_YES_S_NO], [1],
			     [Define to 1 if `no' is a member of `struct yes_s'.])],,
		   [struct sub { int x; };
		    struct yes_s { int yes; struct sub substruct; };])
  AC_CHECK_MEMBER([struct yes_s.substruct],
		  [AC_DEFINE([HAVE_STRUCT_YES_S_SUBSTRUCT], [1],
			     [Define to 1 if `substruct' is a member of `struct yes_s'.])],,
		   [struct sub { int x; };
		    struct yes_s { int yes; struct sub substruct; };])]],
[AT_CHECK_DEFINES(
[/* #undef HAVE_STRUCT_YES_S_NO */
#define HAVE_STRUCT_YES_S_SUBSTRUCT 1
#define HAVE_STRUCT_YES_S_YES 1
])])

# AC_CHECK_MEMBERS
# ----------------
# Check that it performs the correct actions.
# Must define HAVE_STRUCT_YES_S_YES, but not HAVE_STRUCT_YES_S_NO.
AT_CHECK_MACRO([AC_CHECK_MEMBERS],
[[AC_CHECK_MEMBERS([struct yes_s.yes, struct yes_s.no, struct yes_s.substruct],,,
		   [struct sub { int x; };
		    struct yes_s { int yes; struct sub substruct; };])]],
[AT_CHECK_DEFINES(
[/* #undef HAVE_STRUCT_YES_S_NO */
#define HAVE_STRUCT_YES_S_SUBSTRUCT 1
#define HAVE_STRUCT_YES_S_YES 1
])
AT_CHECK([grep 'yes.*member of.*yes_s' config.h], [], [ignore])
])


# AC_CHECK_ALIGNOF
# ----------------
AT_CHECK_MACRO_CROSS([AC_CHECK_ALIGNOF],
[[AC_CHECK_ALIGNOF(char)
AC_CHECK_ALIGNOF(charchar,
[[#include <stddef.h>
#include <stdio.h>
typedef char charchar[2];]])
AC_CHECK_ALIGNOF(charcharchar)
]],
[AT_CHECK_DEFINES(
[#define ALIGNOF_CHAR 1
#define ALIGNOF_CHARCHAR 1
#define ALIGNOF_CHARCHARCHAR 0
])])


# AC_CHECK_ALIGNOF struct
# -----------------------
AT_CHECK_MACRO_CROSS([AC_CHECK_ALIGNOF struct],
[[AC_CHECK_ALIGNOF([struct { char c; }])
AC_CHECK_ALIGNOF([struct nosuchstruct])
]],
[AT_CHECK([[grep "#define ALIGNOF_STRUCT___CHAR_C___ [1-9]" config.h]],
	 0, ignore)
AT_CHECK([[grep "#define ALIGNOF_STRUCT_NOSUCHSTRUCT 0" config.h]],
	 0, ignore)
])

# AC_CHECK_SIZEOF
# ---------------
AT_CHECK_MACRO_CROSS([AC_CHECK_SIZEOF],
[[AC_CHECK_SIZEOF(char)
AC_CHECK_SIZEOF(charchar,,
[[#include <stdio.h>
typedef char charchar[2];]])
AC_CHECK_SIZEOF(charcharchar)
]],
[AT_CHECK_DEFINES(
[#define SIZEOF_CHAR 1
#define SIZEOF_CHARCHAR 2
#define SIZEOF_CHARCHARCHAR 0
])])


# AC_CHECK_SIZEOF struct
# ----------------------
AT_CHECK_MACRO_CROSS([AC_CHECK_SIZEOF struct],
[[AC_C_CONST
AC_CHECK_SIZEOF([struct x], [], [struct x { char c; int x; };])
AC_CHECK_SIZEOF([const struct x], [], [struct x { const char *p; int x; };])
AC_CHECK_SIZEOF([struct nosuchstruct])
# Taken from autoconf.texi:Generic Compiler Characteristics.
AC_CHECK_SIZEOF([int *])
]],
[AT_CHECK([[grep "#define SIZEOF_STRUCT_X [1-9]" config.h]],
	 0, ignore)
AT_CHECK([[grep "#define SIZEOF_CONST_STRUCT_X [1-9]" config.h]],
	 0, ignore)
AT_CHECK([[grep "#define SIZEOF_STRUCT_NOSUCHSTRUCT 0" config.h]],
	 0, ignore)
AT_CHECK([[grep "#define SIZEOF_INT_P [1-9]" config.h]],
	 0, ignore)
])


# AC_CHECK_TYPES
# --------------
# Check that it performs the correct actions.
# Must define HAVE_STRUCT_YES_S, HAVE_INT, but not HAVE_STRUCT_NO_S.
# `int' and `struct yes_s' are both checked to test both the compiler
# builtin types, and defined types.
AT_CHECK_MACRO([AC_CHECK_TYPES],
[[AC_CHECK_TYPES([int, struct yes_s, struct no_s],,,
		 [struct yes_s { int yes ;} ;])]],
[AT_CHECK_DEFINES(
[#define HAVE_INT 1
/* #undef HAVE_STRUCT_NO_S */
#define HAVE_STRUCT_YES_S 1
])])


# AC_CHECK_TYPES
# --------------
# Check that we properly dispatch properly to the old implementation
# or to the new one.
AT_SETUP([AC_CHECK_TYPES: backward compatibility])

AT_DATA([configure.ac],
[[AC_INIT
define([_AC_CHECK_TYPE_NEW], [NEW])
define([_AC_CHECK_TYPE_OLD], [OLD])
#(cut-from-here
AC_CHECK_TYPE(ptrdiff_t)
AC_CHECK_TYPE(ptrdiff_t, int)
AC_CHECK_TYPE(quad, long long int)
AC_CHECK_TYPE(table_42, [int[42]])
# Nice machine!
AC_CHECK_TYPE(uint8_t, uint65536_t)
AC_CHECK_TYPE(a,b,c,d)
#to-here)
AC_OUTPUT
]])

AT_CHECK_AUTOCONF
AT_CHECK([[sed -e '/^#(cut-from-here/,/^#to-here)/!d' -e '/^#/d' configure]],
	 0,
	 [NEW
OLD
OLD
OLD
OLD
NEW
])

AT_CLEANUP


# AC_CHECK_FILES
# --------------
# FIXME: To really test HAVE_AC_EXISTS2 and HAVE_AC_MISSING2 we need to
# open AH_TEMPLATE to `configure.ac', which is not yet the case.
AT_CHECK_MACRO([AC_CHECK_FILES],
[touch at-exists1 at-exists2
ac_exists2=at-exists2
ac_missing2=at-missing2
AC_CHECK_FILES(at-exists1 at-missing1 $ac_exists2 $ac_missing2)
rm at-exists1 at-exists2],
[AT_CHECK_DEFINES(
[#define HAVE_AT_EXISTS1 1
/* #undef HAVE_AT_MISSING1 */
])])



## ------------------------------ ##
## AC_CHECK_PROG & AC_PATH_PROG.  ##
## ------------------------------ ##


# AT_CHECK_PROGS_PREPARE
# ----------------------
# Create a sub directory `path' with 6 subdirs which all 7 contain
# an executable `tool'. `6' contains a `better' tool.
m4_define([AT_CHECK_PROGS_PREPARE],
[mkdir path

cat >path/tool <<\EOF
#! /bin/sh
exit 0
EOF
chmod +x path/tool

for i in 1 2 3 4 5 6
do
  mkdir path/$i
  cp path/tool path/$i
done
cp path/tool path/6/better])


# -------------------------------- #
# AC_CHECK_PROG & AC_CHECK_PROGS.  #
# -------------------------------- #

AT_SETUP([AC_CHECK_PROG & AC_CHECK_PROGS])

AT_CHECK_PROGS_PREPARE

AT_DATA([configure.ac],
[[AC_INIT
pwd=`pwd`
p="1${PATH_SEPARATOR}2${PATH_SEPARATOR}3${PATH_SEPARATOR}4${PATH_SEPARATOR}5${PATH_SEPARATOR}6"
path=`echo $p | sed -e 's,\([[0-9]]\),'"$pwd"'/path/\1,g'`
fail=false

AC_CHECK_PROG(TOOL1, tool, found, not-found, $path)
test "$TOOL1" = found || fail=:

# Yes, the semantics of this macro is weird.
AC_CHECK_PROG(TOOL2, tool,, not-found, $path)
test "$TOOL2" = not-found || fail=:

AC_CHECK_PROG(TOOL3, tool, tool, not-found, $path, $pwd/path/1/tool)
test "$TOOL3" = "$pwd/path/2/tool" || fail=:

AC_CHECK_PROG(TOOL4, better, better, not-found, $path, $pwd/path/1/tool)
test "$TOOL4" = better || fail=:

# When a tool is not found, and no value is given for not-found,
# the variable is left empty.
AC_CHECK_PROGS(TOOL5, missing,, $path)
test -z "$TOOL5" || fail=:

AC_CHECK_PROGS(TOOL6, missing tool better,, $path)
test "$TOOL6" = tool || fail=:

# No AC-OUTPUT, we don't need config.status.
$fail &&
  AC_MSG_ERROR([[CHECK_PROG failed]])
AS_EXIT(0)
]])

AT_CHECK_AUTOCONF
AT_CHECK_CONFIGURE

AT_CLEANUP



## ---------------- ##
## AC_C_BIGENDIAN.  ##
## ---------------- ##

AT_SETUP([AC_C_BIGENDIAN])
AT_KEYWORDS([cross])

# Make sure that AC_C_BIGENDIAN behave the same whether we are
# cross-compiling or not.

_AT_CHECK_AC_MACRO(
  [[AC_C_BIGENDIAN(
      [ac_endian=big],
      [ac_endian=little],
      [ac_endian=unknown],
      [ac_endian=universal])
   echo $ac_endian > at-endian
]])

rm -f config.hin  # So that next run of autoheader is quiet.
_AT_CHECK_AC_MACRO(
  [[# Force cross compiling.
   cross_compiling=yes
   ac_tool_warned=yes
   AC_C_BIGENDIAN(
     [ac_endian=big],
     [ac_endian=little],
     [ac_endian=unknown],
     [ac_endian=universal])
   ac_prevendian=`cat at-endian`
   # Check that we have found the same result as in the previous run
   # or unknown (because the cross-compiling check is allowed to fail;
   # although it might be interesting to suppress this comparison, just
   # to know on which system it fails if it ever does).
   if test $ac_endian != $ac_prevendian && test $ac_endian != unknown; then
     AC_MSG_ERROR([unexpected endianness: first run found '$ac_prevendian' but second run found '$ac_endian'])
   fi
]])

# Make sure AC_C_BIGENDIAN with no argument will create a config.h template
# containing "WORDS_BIGENDIAN".
AT_CONFIGURE_AC([[AC_C_BIGENDIAN]])
# --force is necessary, the computer might be too fast.
AT_CHECK_AUTOHEADER([--force])
AT_CHECK([grep WORDS_BIGENDIAN config.hin], [], [ignore])

AT_CLEANUP


# ------------------------------ #
# AC_PATH_PROG & AC_PATH_PROGS.  #
# ------------------------------ #

AT_SETUP([AC_PATH_PROG & AC_PATH_PROGS])

AT_CHECK_PROGS_PREPARE

AT_DATA([configure.ac],
[[AC_INIT
pwd=`pwd`
p="1${PATH_SEPARATOR}2${PATH_SEPARATOR}3${PATH_SEPARATOR}4${PATH_SEPARATOR}5${PATH_SEPARATOR}6"
path=`echo $p | sed -e 's,\([[0-9]]\),'"$pwd"'/path/\1,g'`
fail=false

AC_PATH_PROG(TOOL1, tool, not-found, $path)
test "$TOOL1" = "$pwd/path/1/tool" || fail=:

AC_PATH_PROG(TOOL2, better, not-found, $path)
test "$TOOL2" = "$pwd/path/6/better" || fail=:

# When a tool is not found, and no value is given for not-found,
# the variable is left empty.
AC_PATH_PROGS(TOOL3, missing,, $path)
test -z "$TOOL3" || fail=:

AC_PATH_PROGS(TOOL4, missing tool better,, $path)
test "$TOOL4" = "$pwd/path/1/tool" || fail=:

# No AC-OUTPUT, we don't need config.status.
$fail &&
  AC_MSG_ERROR([[PATH_PROG failed]])
AS_EXIT(0)
]])

AT_CHECK_AUTOCONF
AT_CHECK_CONFIGURE

AT_CLEANUP



# ----------------------------- #
# AC_PATH_PROGS_FEATURE_CHECK.  #
# ----------------------------- #

AT_SETUP([AC_PATH_PROGS_FEATURE_CHECK])

# This test doesn't work if `pwd` contains white space
case `pwd` in
  *\ * | *\	*) AT_CHECK([exit 77]) ;;
esac

AT_CHECK_PROGS_PREPARE

AT_DATA([configure.ac],
[[AC_INIT
pwd=`pwd`
p="1${PATH_SEPARATOR}2${PATH_SEPARATOR}3${PATH_SEPARATOR}4${PATH_SEPARATOR}5${PATH_SEPARATOR}6"
path=`echo $p | sed -e 's,\([[0-9]]\),'"$pwd"'/path/\1,g'`
fail=false

# Find first candidate and stop search
AC_PATH_PROGS_FEATURE_CHECK(TOOL1, [tool better],
  [$ac_path_TOOL1 && ac_cv_path_TOOL1=$ac_path_TOOL1 ac_path_TOOL1_found=:],
  fail=:, $path)
test -z "$TOOL1" || fail=:
test "$ac_cv_path_TOOL1" = "$pwd/path/1/tool" || fail=:

# Keep searching each candidate
AC_PATH_PROGS_FEATURE_CHECK(TOOL2, [tool better],
  [$ac_path_TOOL2 && ac_cv_path_TOOL2=$ac_path_TOOL2],
  fail=:, $path)
test "$ac_cv_path_TOOL2" = "$pwd/path/6/better" || fail=:

# Only accept better candidate
AC_PATH_PROGS_FEATURE_CHECK(TOOL3, [tool better],
  [case "$ac_path_TOOL3" in #(
    *better) ac_cv_path_TOOL3=$ac_path_TOOL3;;
  esac],
  fail=:, $path)
test "$ac_cv_path_TOOL3" = "$pwd/path/6/better" || fail=:

# When a tool is not found, and no action is given for not-found,
# the variable is left empty.
AC_PATH_PROGS_FEATURE_CHECK(TOOL4, missing,
  [ac_cv_path_TOOL4=$ac_path_TOOL4], [], $path)
test -z "$ac_cv_path_TOOL4" || fail=:

# Test action when tool is not found
AC_PATH_PROGS_FEATURE_CHECK(TOOL5, missing, [],
  [ac_cv_path_TOOL5='not found'], $path)
test "$ac_cv_path_TOOL5" = "not found" || fail=:

# Test that pre-set tool bypasses feature test
TOOL6=$pwd/path/6/better
AC_PATH_PROGS_FEATURE_CHECK(TOOL6, tool, fail=:, fail=:, $path)
test "$ac_cv_path_TOOL6" = "$pwd/path/6/better" || fail=:

# A blank pre-set does not bypass feature test
TOOL7=
AC_PATH_PROGS_FEATURE_CHECK(TOOL7, [tool better],
  [$ac_path_TOOL7 && ac_cv_path_TOOL7=$ac_path_TOOL7 ac_path_TOOL7_found=:],
  fail=:, $path)
test -z "$TOOL7" || fail=:
test "$ac_cv_path_TOOL7" = "$pwd/path/1/tool" || fail=:

# No AC-OUTPUT, we don't need config.status.
$fail &&
  AC_MSG_ERROR([[PATH_PROG failed]])
AS_EXIT(0)
]])

AT_CHECK_AUTOCONF
AT_CHECK_CONFIGURE

AT_CLEANUP




## -------------- ##
## AC_PATH_XTRA.  ##
## -------------- ##


AT_SETUP([AC_PATH_XTRA])

_AT_CHECK_AC_MACRO([AC_PATH_XTRA])

# Check X_DISPLAY_MISSING.
AT_CHECK_CONFIGURE([--without-x])
AT_CHECK_DEFINES(
[#define X_DISPLAY_MISSING 1
])

AT_CLEANUP


## ------------------------------- ##
## Obsolete non-updatable macros.  ##
## ------------------------------- ##


AT_CHECK_MACRO([AC_SYS_RESTARTABLE_SYSCALLS], , ,[-W no-obsolete])
AT_CHECK_MACRO([AC_FUNC_SETVBUF_REVERSED], , ,[-W no-obsolete])
AT_CHECK_MACRO([AC_FUNC_WAIT3], , ,[-W no-obsolete])