A small piece of note for Linux toolkit.

After I upgraded gcc from version of 4.4.7 to version of 7.4.0 on CentOS 6.5, some ridiculous bugs happened when I linked my project to gtest. So I rebuilt gtest using the newer gcc, however, bugs remained. In the end, I found that cmake did not use the newer gcc when I was typing cmake .. command, I guessed that was the key.

How to upgrade gcc to a newer version

install development tools

1
2
yum groupinstall "Development Tools"
yum install glibc-static libstdc++-static

download gcc package

http://mirror.hust.edu.cn/gnu/gcc/ turned out to be the most fastest mirror in China.

build gcc

1
2
3
4
5
6
7
8
tar -Jxvf gcc-7.4.0.tar.xz
cd gcc-7.4.0
./contrib/download_prerequisits
mkdir BUILD
cd BUILD
../configure --enable-checking=release --enable-languages=c,c++ --disable-multilib
make -j4
sudo make install

Note that ./contrib/download_prerequisits will download 4 packages:

  • mpc-1.0.3.tar.gc

  • mpfr-3.1.4.tar.bz2

  • gmp-6.1.9.tar.bz2

  • isl-0.16.1.tar.bz2

new feature support testing

v7.4.0 support c++17, here is a sample from cppreference.

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
/// cpp17_any.cc
#include <any>
#include <iostream>

int main()
{
std::cout << std::boolalpha;

// any type
std::any a = 1;
std::cout << a.type().name() << ": " << std::any_cast<int>(a) << '\n';
a = 3.14;
std::cout << a.type().name() << ": " << std::any_cast<double>(a) << '\n';
a = true;
std::cout << a.type().name() << ": " << std::any_cast<bool>(a) << '\n';

// bad cast
try
{
a = 1;
std::cout << std::any_cast<float>(a) << '\n';
}
catch (const std::bad_any_cast& e)
{
std::cout << e.what() << '\n';
}

// has value
a = 1;
if (a.has_value())
{
std::cout << a.type().name() << '\n';
}

// reset
a.reset();
if (!a.has_value())
{
std::cout << "no value\n";
}

// pointer to contained data
a = 1;
int* i = std::any_cast<int>(&a);
std::cout << *i << "\n";
}
1
2
g++ cpp17_any.cc -std=c++17
./a.out

It would raise linking errors for libraries compatibility.

update the system newergcc linker

1
2
3
4
5
6
7
8
9
10
find . -name *libstdc++* # find the newer lib
strings ./prev-x86_64-pc-linux-gnu/libstdc++-v3/src/.libs/libstdc++.so.6.0.24 | grep 'CXXABI'
strings ./prev-x86_64-pc-linux-gnu/libstdc++-v3/src/.libs/libstdc++.so.6.0.24 | grep 'GLIBCXX'
sudo cp ./prev-x86_64-pc-linux-gnu/libstdc++-v3/src/.libs/libstdc++.so.6.0.24 /usr/lib64/
strings /usr/lib64/libstdc++.so.6.0.24 | grep 'GLIBCXX' # check lib
strings /usr/lib64/libstdc++.so.6.0.24 | grep 'CXXABI'
sudo rm /usr/lib64/libstdc++.so.6
sudo ln -s /usr/lib64/libstdc++.so.6.0.24 /usr/lib64/libstdc++.so.6
strings /usr/lib64/libstdc++.so.6 | grep 'CXXABI' # check lib
strings /usr/lib64/libstdc++.so.6 | grep 'GLIBCXX'

compile and run again the output would be:

1
2
3
4
5
6
7
i: 1
d: 3.14
b: true
bad any_cast
i
no value
1

Note that gdb would not be compatible for the newer gcc, you should upgrade it too.

How to specify the newer version gccfor cmake

bad approach

For the sake of specify the newer version of gcc, I tried to modify the CMakeList.txt by adding some like the following:

1
2
set(CMAKE_C_COMPILER "/usr/local/bin/gcc")
set(CMAKE_CXX_COMPILER "/usr/local/bin/g++")

which reminds me it is a bad idea, even though I had backed up a copy.

ideal approach

BUT, export is a ideal approach. that is exporting system variables of CXX and CC to CMake’s cache before cmake:

1
2
export CC=/usr/local/bin/gcc 
export CXX=/usr/local/bin/g++

The export only needs to be done once, the first time you configure the project, then those values will be read from the CMake cache.

reasonable explaination

I recommend against overriding the CMAKE_C(XX)_COMPILER value for two main reasons: because it won’t play well with CMake’s cache and because it breaks compiler checks and tooling detection.

When using the set command, you have three options:

  • without cache, to create a normal variable
  • with cache, to create a cached variable
  • force cache, to always force the cache value when configuring

Let’s see what happens for the three possible calls to set:

Without cache

1
2
set(CMAKE_C_COMPILER /usr/bin/clang)
set(CMAKE_CXX_COMPILER /usr/bin/clang++)

When doing this, you create a “normal” variable CMAKE_C(XX)_COMPILER that hides the cache variable of the same name. That means your compiler is now hard-coded in your build script and you cannot give it a custom value. This will be a problem if you have multiple build environments with different compilers. You could just update your script each time you want to use a different compiler, but that removes the value of using CMake in the first place.

Ok, then, let’s update the cache…

With cache

1
2
set(CMAKE_C_COMPILER /usr/bin/clang CACHE PATH "")
set(CMAKE_CXX_COMPILER /usr/bin/clang++ CACHE PATH "")

This version will just “not work”. The CMAKE_C(XX)_COMPILER variable is already in the cache, so it won’t get updated unless you force it.

Ah… let’s use the force, then…

Force cache

1
2
set(CMAKE_C_COMPILER /usr/bin/clang CACHE PATH "" FORCE)
set(CMAKE_CXX_COMPILER /usr/bin/clang++ CACHE PATH "" FORCE)

This is almost the same as the “normal” variable version, the only difference is your value will be set in the cache, so users can see it. But any change will be overwritten by the set command.

Breaking compiler checks and tooling

Early in the configuration process, CMake performs checks on the compiler: Does it work? Is it able to produce executables? etc. It also uses the compiler to detect related tools, like ar and ranlib. When you override the compiler value in a script, it’s “too late”, all checks and detections are already done.

For instance, on my machine with gcc as default compiler, when using the set command to /usr/bin/clang, ar is set to /usr/bin/gcc-ar-7. When using an export before running CMake it is set to /usr/lib/llvm-3.8/bin/llvm-ar.

How to upgrade gdb

download the newest version of gdb

http://mirror.hust.edu.cn/gnu/gdb/

specify the newer gcc version to build

1
2
3
mkdir BUILD & cd BUILD/
export CC=/usr/local/bin/gcc
export CXX=/usr/local/bin/g++

make it support TUI

1
2
3
../configure --enable-tui --with-python=yes
make -j8
sudo make install

make it support STL pretty print message

copy the following script to local with name like .gdbinit

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
#                                                                                                        
# STL GDB evaluators/views/utilities - 1.03
#
# The new GDB commands:
# are entirely non instrumental
# do not depend on any "inline"(s) - e.g. size(), [], etc
# are extremely tolerant to debugger settings
#
# This file should be "included" in .gdbinit as following:
# source stl-views.gdb or just paste it into your .gdbinit file
#
# The following STL containers are currently supported:
#
# std::vector<T> -- via pvector command
# std::list<T> -- via plist or plist_member command
# std::map<T,T> -- via pmap or pmap_member command
# std::multimap<T,T> -- via pmap or pmap_member command
# std::set<T> -- via pset command
# std::multiset<T> -- via pset command
# std::deque<T> -- via pdequeue command
# std::stack<T> -- via pstack command
# std::queue<T> -- via pqueue command
# std::priority_queue<T> -- via ppqueue command
# std::bitset<n> -- via pbitset command
# std::string -- via pstring command
# std::widestring -- via pwstring command
#
# The end of this file contains (optional) C++ beautifiers
# Make sure your debugger supports $argc
#
# Simple GDB Macros writen by Dan Marinescu (H-PhD) - License GPL
# Inspired by intial work of Tom Malnar,
# Tony Novac (PhD) / Cornell / Stanford,
# Gilad Mishne (PhD) and Many Many Others.
# Contact: dan_c_marinescu@yahoo.com (Subject: STL)
#
# Modified to work with g++ 4.3 by Anders Elton
# Also added _member functions, that instead of printing the entire class in map, prints a member.



#
# std::vector<>
#

define pvector
if $argc == 0
help pvector
else
set $size = $arg0._M_impl._M_finish - $arg0._M_impl._M_start
set $capacity = $arg0._M_impl._M_end_of_storage - $arg0._M_impl._M_start
set $size_max = $size - 1
end
if $argc == 1
set $i = 0
while $i < $size
printf "elem[%u]: ", $i
p *($arg0._M_impl._M_start + $i)
set $i++
end
end
if $argc == 2
set $idx = $arg1
if $idx < 0 || $idx > $size_max
printf "idx1, idx2 are not in acceptable range: [0..%u].\n", $size_max
else
printf "elem[%u]: ", $idx
p *($arg0._M_impl._M_start + $idx)
end
end
if $argc == 3
set $start_idx = $arg1
set $stop_idx = $arg2
if $start_idx > $stop_idx
set $tmp_idx = $start_idx
set $start_idx = $stop_idx
set $stop_idx = $tmp_idx
end
if $start_idx < 0 || $stop_idx < 0 || $start_idx > $size_max || $stop_idx > $size_max
printf "idx1, idx2 are not in acceptable range: [0..%u].\n", $size_max
else
set $i = $start_idx
while $i <= $stop_idx
printf "elem[%u]: ", $i
p *($arg0._M_impl._M_start + $i)
set $i++
end
end
end
if $argc > 0
printf "Vector size = %u\n", $size
printf "Vector capacity = %u\n", $capacity
printf "Element "
whatis $arg0._M_impl._M_start
end
end

document pvector
Prints std::vector<T> information.
Syntax: pvector <vector> <idx1> <idx2>
Note: idx, idx1 and idx2 must be in acceptable range [0..<vector>.size()-1].
Examples:
pvector v - Prints vector content, size, capacity and T typedef
pvector v 0 - Prints element[idx] from vector
pvector v 1 2 - Prints elements in range [idx1..idx2] from vector
end

#
# std::list<>
#

define plist
if $argc == 0
help plist
else
set $head = &$arg0._M_impl._M_node
set $current = $arg0._M_impl._M_node._M_next
set $size = 0
while $current != $head
if $argc == 2
printf "elem[%u]: ", $size
p *($arg1*)($current + 1)
end
if $argc == 3
if $size == $arg2
printf "elem[%u]: ", $size
p *($arg1*)($current + 1)
end
end
set $current = $current._M_next
set $size++
end
printf "List size = %u \n", $size
if $argc == 1
printf "List "
whatis $arg0
printf "Use plist <variable_name> <element_type> to see the elements in the list.\n"
end
end
end

document plist
Prints std::list<T> information.
Syntax: plist <list> <T> <idx>: Prints list size, if T defined all elements or just element at idx
Examples:
plist l - prints list size and definition
plist l int - prints all elements and list size
plist l int 2 - prints the third element in the list (if exists) and list size
end

define plist_member
if $argc == 0
help plist_member
else
set $head = &$arg0._M_impl._M_node
set $current = $arg0._M_impl._M_node._M_next
set $size = 0
while $current != $head
if $argc == 3
printf "elem[%u]: ", $size
p (*($arg1*)($current + 1)).$arg2
end
if $argc == 4
if $size == $arg3
printf "elem[%u]: ", $size
p (*($arg1*)($current + 1)).$arg2
end
end
set $current = $current._M_next
set $size++
end
printf "List size = %u \n", $size
if $argc == 1
printf "List "
whatis $arg0
printf "Use plist_member <variable_name> <element_type> <member> to see the elements in the list.\n"
end
end
end

document plist_member
Prints std::list<T> information.
Syntax: plist <list> <T> <idx>: Prints list size, if T defined all elements or just element at idx
Examples:
plist_member l int member - prints all elements and list size
plist_member l int member 2 - prints the third element in the list (if exists) and list size
end


#
# std::map and std::multimap
#

define pmap
if $argc == 0
help pmap
else
set $tree = $arg0
set $i = 0
set $node = $tree._M_t._M_impl._M_header._M_left
set $end = $tree._M_t._M_impl._M_header
set $tree_size = $tree._M_t._M_impl._M_node_count
if $argc == 1
printf "Map "
whatis $tree
printf "Use pmap <variable_name> <left_element_type> <right_element_type> to see the elements in the map.\n"
end
if $argc == 3
while $i < $tree_size
set $value = (void *)($node + 1)
printf "elem[%u].left: ", $i
p *($arg1*)$value
set $value = $value + sizeof($arg1)
printf "elem[%u].right: ", $i
p *($arg2*)$value
if $node._M_right != 0
set $node = $node._M_right
while $node._M_left != 0
set $node = $node._M_left
end
else
set $tmp_node = $node._M_parent
while $node == $tmp_node._M_right
set $node = $tmp_node
set $tmp_node = $tmp_node._M_parent
end
if $node._M_right != $tmp_node
set $node = $tmp_node
end
end
set $i++
end
end
if $argc == 4
set $idx = $arg3
set $ElementsFound = 0
while $i < $tree_size
set $value = (void *)($node + 1)
if *($arg1*)$value == $idx
printf "elem[%u].left: ", $i
p *($arg1*)$value
set $value = $value + sizeof($arg1)
printf "elem[%u].right: ", $i
p *($arg2*)$value
set $ElementsFound++
end
if $node._M_right != 0
set $node = $node._M_right
while $node._M_left != 0
set $node = $node._M_left
end
else
set $tmp_node = $node._M_parent
while $node == $tmp_node._M_right
set $node = $tmp_node
set $tmp_node = $tmp_node._M_parent
end
if $node._M_right != $tmp_node
set $node = $tmp_node
end
end
set $i++
end
printf "Number of elements found = %u\n", $ElementsFound
end
if $argc == 5
set $idx1 = $arg3
set $idx2 = $arg4
set $ElementsFound = 0
while $i < $tree_size
set $value = (void *)($node + 1)
set $valueLeft = *($arg1*)$value
set $valueRight = *($arg2*)($value + sizeof($arg1))
if $valueLeft == $idx1 && $valueRight == $idx2
printf "elem[%u].left: ", $i
p $valueLeft
printf "elem[%u].right: ", $i
p $valueRight
set $ElementsFound++
end
if $node._M_right != 0
set $node = $node._M_right
while $node._M_left != 0
set $node = $node._M_left
end
else
set $tmp_node = $node._M_parent
while $node == $tmp_node._M_right
set $node = $tmp_node
set $tmp_node = $tmp_node._M_parent
end
if $node._M_right != $tmp_node
set $node = $tmp_node
end
end
set $i++
end
printf "Number of elements found = %u\n", $ElementsFound
end
printf "Map size = %u\n", $tree_size
end
end

document pmap
Prints std::map<TLeft and TRight> or std::multimap<TLeft and TRight> information. Works for std::multimap as well.
Syntax: pmap <map> <TtypeLeft> <TypeRight> <valLeft> <valRight>: Prints map size, if T defined all elements or just element(s) with val(s)
Examples:
pmap m - prints map size and definition
pmap m int int - prints all elements and map size
pmap m int int 20 - prints the element(s) with left-value = 20 (if any) and map size
pmap m int int 20 200 - prints the element(s) with left-value = 20 and right-value = 200 (if any) and map size
end


define pmap_member
if $argc == 0
help pmap_member
else
set $tree = $arg0
set $i = 0
set $node = $tree._M_t._M_impl._M_header._M_left
set $end = $tree._M_t._M_impl._M_header
set $tree_size = $tree._M_t._M_impl._M_node_count
if $argc == 1
printf "Map "
whatis $tree
printf "Use pmap <variable_name> <left_element_type> <right_element_type> to see the elements in the map.\n"
end
if $argc == 5
while $i < $tree_size
set $value = (void *)($node + 1)
printf "elem[%u].left: ", $i
p (*($arg1*)$value).$arg2
set $value = $value + sizeof($arg1)
printf "elem[%u].right: ", $i
p (*($arg3*)$value).$arg4
if $node._M_right != 0
set $node = $node._M_right
while $node._M_left != 0
set $node = $node._M_left
end
else
set $tmp_node = $node._M_parent
while $node == $tmp_node._M_right
set $node = $tmp_node
set $tmp_node = $tmp_node._M_parent
end
if $node._M_right != $tmp_node
set $node = $tmp_node
end
end
set $i++
end
end
if $argc == 6
set $idx = $arg5
set $ElementsFound = 0
while $i < $tree_size
set $value = (void *)($node + 1)
if *($arg1*)$value == $idx
printf "elem[%u].left: ", $i
p (*($arg1*)$value).$arg2
set $value = $value + sizeof($arg1)
printf "elem[%u].right: ", $i
p (*($arg3*)$value).$arg4
set $ElementsFound++
end
if $node._M_right != 0
set $node = $node._M_right
while $node._M_left != 0
set $node = $node._M_left
end
else
set $tmp_node = $node._M_parent
while $node == $tmp_node._M_right
set $node = $tmp_node
set $tmp_node = $tmp_node._M_parent
end
if $node._M_right != $tmp_node
set $node = $tmp_node
end
end
set $i++
end
printf "Number of elements found = %u\n", $ElementsFound
end
printf "Map size = %u\n", $tree_size
end
end

document pmap_member
Prints std::map<TLeft and TRight> or std::multimap<TLeft and TRight> information. Works for std::multimap as well.
Syntax: pmap <map> <TtypeLeft> <TypeRight> <valLeft> <valRight>: Prints map size, if T defined all elements or just element(s) with val(s)
Examples:
pmap_member m class1 member1 class2 member2 - prints class1.member1 : class2.member2
pmap_member m class1 member1 class2 member2 lvalue - prints class1.member1 : class2.member2 where class1 == lvalue
end


#
# std::set and std::multiset
#

define pset
if $argc == 0
help pset
else
set $tree = $arg0
set $i = 0
set $node = $tree._M_t._M_impl._M_header._M_left
set $end = $tree._M_t._M_impl._M_header
set $tree_size = $tree._M_t._M_impl._M_node_count
if $argc == 1
printf "Set "
whatis $tree
printf "Use pset <variable_name> <element_type> to see the elements in the set.\n"
end
if $argc == 2
while $i < $tree_size
set $value = (void *)($node + 1)
printf "elem[%u]: ", $i
p *($arg1*)$value
if $node._M_right != 0
set $node = $node._M_right
while $node._M_left != 0
set $node = $node._M_left
end
else
set $tmp_node = $node._M_parent
while $node == $tmp_node._M_right
set $node = $tmp_node
set $tmp_node = $tmp_node._M_parent
end
if $node._M_right != $tmp_node
set $node = $tmp_node
end
end
set $i++
end
end
if $argc == 3
set $idx = $arg2
set $ElementsFound = 0
while $i < $tree_size
set $value = (void *)($node + 1)
if *($arg1*)$value == $idx
printf "elem[%u]: ", $i
p *($arg1*)$value
set $ElementsFound++
end
if $node._M_right != 0
set $node = $node._M_right
while $node._M_left != 0
set $node = $node._M_left
end
else
set $tmp_node = $node._M_parent
while $node == $tmp_node._M_right
set $node = $tmp_node
set $tmp_node = $tmp_node._M_parent
end
if $node._M_right != $tmp_node
set $node = $tmp_node
end
end
set $i++
end
printf "Number of elements found = %u\n", $ElementsFound
end
printf "Set size = %u\n", $tree_size
end
end

document pset
Prints std::set<T> or std::multiset<T> information. Works for std::multiset as well.
Syntax: pset <set> <T> <val>: Prints set size, if T defined all elements or just element(s) having val
Examples:
pset s - prints set size and definition
pset s int - prints all elements and the size of s
pset s int 20 - prints the element(s) with value = 20 (if any) and the size of s
end



#
# std::dequeue
#

define pdequeue
if $argc == 0
help pdequeue
else
set $size = 0
set $start_cur = $arg0._M_impl._M_start._M_cur
set $start_last = $arg0._M_impl._M_start._M_last
set $start_stop = $start_last
while $start_cur != $start_stop
p *$start_cur
set $start_cur++
set $size++
end
set $finish_first = $arg0._M_impl._M_finish._M_first
set $finish_cur = $arg0._M_impl._M_finish._M_cur
set $finish_last = $arg0._M_impl._M_finish._M_last
if $finish_cur < $finish_last
set $finish_stop = $finish_cur
else
set $finish_stop = $finish_last
end
while $finish_first != $finish_stop
p *$finish_first
set $finish_first++
set $size++
end
printf "Dequeue size = %u\n", $size
end
end

document pdequeue
Prints std::dequeue<T> information.
Syntax: pdequeue <dequeue>: Prints dequeue size, if T defined all elements
Deque elements are listed "left to right" (left-most stands for front and right-most stands for back)
Example:
pdequeue d - prints all elements and size of d
end



#
# std::stack
#

define pstack
if $argc == 0
help pstack
else
set $start_cur = $arg0.c._M_impl._M_start._M_cur
set $finish_cur = $arg0.c._M_impl._M_finish._M_cur
set $size = $finish_cur - $start_cur
set $i = $size - 1
while $i >= 0
p *($start_cur + $i)
set $i--
end
printf "Stack size = %u\n", $size
end
end

document pstack
Prints std::stack<T> information.
Syntax: pstack <stack>: Prints all elements and size of the stack
Stack elements are listed "top to buttom" (top-most element is the first to come on pop)
Example:
pstack s - prints all elements and the size of s
end



#
# std::queue
#

define pqueue
if $argc == 0
help pqueue
else
set $start_cur = $arg0.c._M_impl._M_start._M_cur
set $finish_cur = $arg0.c._M_impl._M_finish._M_cur
set $size = $finish_cur - $start_cur
set $i = 0
while $i < $size
p *($start_cur + $i)
set $i++
end
printf "Queue size = %u\n", $size
end
end

document pqueue
Prints std::queue<T> information.
Syntax: pqueue <queue>: Prints all elements and the size of the queue
Queue elements are listed "top to bottom" (top-most element is the first to come on pop)
Example:
pqueue q - prints all elements and the size of q
end



#
# std::priority_queue
#

define ppqueue
if $argc == 0
help ppqueue
else
set $size = $arg0.c._M_impl._M_finish - $arg0.c._M_impl._M_start
set $capacity = $arg0.c._M_impl._M_end_of_storage - $arg0.c._M_impl._M_start
set $i = $size - 1
while $i >= 0
p *($arg0.c._M_impl._M_start + $i)
set $i--
end
printf "Priority queue size = %u\n", $size
printf "Priority queue capacity = %u\n", $capacity
end
end

document ppqueue
Prints std::priority_queue<T> information.
Syntax: ppqueue <priority_queue>: Prints all elements, size and capacity of the priority_queue
Priority_queue elements are listed "top to buttom" (top-most element is the first to come on pop)
Example:
ppqueue pq - prints all elements, size and capacity of pq
end



#
# std::bitset
#

define pbitset
if $argc == 0
help pbitset
else
p /t $arg0._M_w
end
end

document pbitset
Prints std::bitset<n> information.
Syntax: pbitset <bitset>: Prints all bits in bitset
Example:
pbitset b - prints all bits in b
end



#
# std::string
#

define pstring
if $argc == 0
help pstring
else
printf "String \t\t\t= \"%s\"\n", $arg0._M_data()
printf "String size/length \t= %u\n", $arg0._M_rep()._M_length
printf "String capacity \t= %u\n", $arg0._M_rep()._M_capacity
printf "String ref-count \t= %d\n", $arg0._M_rep()._M_refcount
end
end

document pstring
Prints std::string information.
Syntax: pstring <string>
Example:
pstring s - Prints content, size/length, capacity and ref-count of string s
end

#
# std::wstring
#

define pwstring
if $argc == 0
help pwstring
else
call printf("WString \t\t= \"%ls\"\n", $arg0._M_data())
printf "WString size/length \t= %u\n", $arg0._M_rep()._M_length
printf "WString capacity \t= %u\n", $arg0._M_rep()._M_capacity
printf "WString ref-count \t= %d\n", $arg0._M_rep()._M_refcount
end
end

document pwstring
Prints std::wstring information.
Syntax: pwstring <wstring>
Example:
pwstring s - Prints content, size/length, capacity and ref-count of wstring s
end

#
# C++ related beautifiers (optional)
#

set print pretty on
set print object on
set print static-members on
set print vtbl on
set print demangle on
set demangle-style gnu-v3
set print sevenbit-strings off

gdb testing example

example code

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
///  vector_test.cc

#include <iostream>
#include <vector>

int main()
{
// Create a vector containing integers
std::vector<int> v = {7, 5, 16, 8};

// Add two more integers to vector
v.push_back(25);
v.push_back(13);

// Iterate and print values of vector
for(int n : v) {
std::cout << n << '\n';
}
return 0;
}

compile it and debug using

1
2
g++ vector_test.cc -std=c++11 -g
gdb a.out

gdb console

1
2
3
4
5
6
7
(gdb) b 9
(gdb) layout src # set source code layout(TUI mode)
(gdb) r
(gdb) pvector v # print all the vector elements
(gdb) n
(gdb) n
(gdb) pvector v 4 5 # check v[4] v[5]

Comments