How to printf a std::string_view in gdb?

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1

Just trying to debug something, and:

(gdb) 

Thread 1 "SciTE" hit Breakpoint 2, PropSetFile::Set (this=this@entry=0x7fffffffbea0, 

    key="LS_COLORS", 

    val="rs=0:di=01;34:ln=01;36:mh=00:pi=40;33:so=01;35:do=01;35:bd=40;33;01:cd=40;33;01:or=40;31;01:mi=00:su=37;41:sg=30;43:ca=30;41:tw=30;42:ow=34;42:st=37;44:ex=01;32:*.tar=01;31:*.tgz=01;31:*.arc=01;31:*.a"...) at ./../src/PropSetFile.cxx:91

91  void PropSetFile::Set(std::string_view key, std::string_view val) {



(gdb) p key

$2 = "LS_COLORS"

(gdb) ptype key

type = std::string_view

Ok, so if I just say p key, then I get its contents printed.

But I want to do a dprintf, meaning a printf:

(gdb) printf "'%s'n", key

'Value can't be converted to integer.

(gdb) printf "'%s'n", key.c_str()

Can't take address of "key" which isn't an lvalue.

(gdb) printf "'%s'n", *(char **)key

Invalid cast.

(gdb) printf "'%s'n", (char *)key

Invalid cast.

(gdb) printf "'%s'n", std::string(key).c_str()

Cannot look up value of a typedef `std::__cxx11::string'.

So, how could I print this variable in a gdb printf/dprintf command?

debugging gdb printf

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asked Jan 3 at 4:31

sdaausdaau

20.4k28154207

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1

Just trying to debug something, and:

(gdb) 

Thread 1 "SciTE" hit Breakpoint 2, PropSetFile::Set (this=this@entry=0x7fffffffbea0, 

    key="LS_COLORS", 

    val="rs=0:di=01;34:ln=01;36:mh=00:pi=40;33:so=01;35:do=01;35:bd=40;33;01:cd=40;33;01:or=40;31;01:mi=00:su=37;41:sg=30;43:ca=30;41:tw=30;42:ow=34;42:st=37;44:ex=01;32:*.tar=01;31:*.tgz=01;31:*.arc=01;31:*.a"...) at ./../src/PropSetFile.cxx:91

91  void PropSetFile::Set(std::string_view key, std::string_view val) {



(gdb) p key

$2 = "LS_COLORS"

(gdb) ptype key

type = std::string_view

Ok, so if I just say p key, then I get its contents printed.

But I want to do a dprintf, meaning a printf:

(gdb) printf "'%s'n", key

'Value can't be converted to integer.

(gdb) printf "'%s'n", key.c_str()

Can't take address of "key" which isn't an lvalue.

(gdb) printf "'%s'n", *(char **)key

Invalid cast.

(gdb) printf "'%s'n", (char *)key

Invalid cast.

(gdb) printf "'%s'n", std::string(key).c_str()

Cannot look up value of a typedef `std::__cxx11::string'.

So, how could I print this variable in a gdb printf/dprintf command?

debugging gdb printf

share|improve this question

asked Jan 3 at 4:31

sdaausdaau

20.4k28154207

add a comment | 

1

1

1

Just trying to debug something, and:

(gdb) 

Thread 1 "SciTE" hit Breakpoint 2, PropSetFile::Set (this=this@entry=0x7fffffffbea0, 

    key="LS_COLORS", 

    val="rs=0:di=01;34:ln=01;36:mh=00:pi=40;33:so=01;35:do=01;35:bd=40;33;01:cd=40;33;01:or=40;31;01:mi=00:su=37;41:sg=30;43:ca=30;41:tw=30;42:ow=34;42:st=37;44:ex=01;32:*.tar=01;31:*.tgz=01;31:*.arc=01;31:*.a"...) at ./../src/PropSetFile.cxx:91

91  void PropSetFile::Set(std::string_view key, std::string_view val) {



(gdb) p key

$2 = "LS_COLORS"

(gdb) ptype key

type = std::string_view

Ok, so if I just say p key, then I get its contents printed.

But I want to do a dprintf, meaning a printf:

(gdb) printf "'%s'n", key

'Value can't be converted to integer.

(gdb) printf "'%s'n", key.c_str()

Can't take address of "key" which isn't an lvalue.

(gdb) printf "'%s'n", *(char **)key

Invalid cast.

(gdb) printf "'%s'n", (char *)key

Invalid cast.

(gdb) printf "'%s'n", std::string(key).c_str()

Cannot look up value of a typedef `std::__cxx11::string'.

So, how could I print this variable in a gdb printf/dprintf command?

debugging gdb printf

share|improve this question

asked Jan 3 at 4:31

sdaausdaau

20.4k28154207

Just trying to debug something, and:

(gdb) 

Thread 1 "SciTE" hit Breakpoint 2, PropSetFile::Set (this=this@entry=0x7fffffffbea0, 

    key="LS_COLORS", 

    val="rs=0:di=01;34:ln=01;36:mh=00:pi=40;33:so=01;35:do=01;35:bd=40;33;01:cd=40;33;01:or=40;31;01:mi=00:su=37;41:sg=30;43:ca=30;41:tw=30;42:ow=34;42:st=37;44:ex=01;32:*.tar=01;31:*.tgz=01;31:*.arc=01;31:*.a"...) at ./../src/PropSetFile.cxx:91

91  void PropSetFile::Set(std::string_view key, std::string_view val) {



(gdb) p key

$2 = "LS_COLORS"

(gdb) ptype key

type = std::string_view

Ok, so if I just say p key, then I get its contents printed.

But I want to do a dprintf, meaning a printf:

(gdb) printf "'%s'n", key

'Value can't be converted to integer.

(gdb) printf "'%s'n", key.c_str()

Can't take address of "key" which isn't an lvalue.

(gdb) printf "'%s'n", *(char **)key

Invalid cast.

(gdb) printf "'%s'n", (char *)key

Invalid cast.

(gdb) printf "'%s'n", std::string(key).c_str()

Cannot look up value of a typedef `std::__cxx11::string'.

So, how could I print this variable in a gdb printf/dprintf command?

debugging gdb printf

debugging gdb printf

share|improve this question

asked Jan 3 at 4:31

sdaausdaau

20.4k28154207

share|improve this question

asked Jan 3 at 4:31

sdaausdaau

20.4k28154207

share|improve this question

share|improve this question

asked Jan 3 at 4:31

sdaausdaau

20.4k28154207

asked Jan 3 at 4:31

sdaausdaau

20.4k28154207

asked Jan 3 at 4:31

sdaausdaau

20.4k28154207

20.4k28154207

add a comment | 

add a comment | 

1 Answer
1

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Here is a workaround using gdb python:

(gdb) break PropSetFile::Set

Breakpoint 4 at 0x555555667700: file ./../src/PropSetFile.cxx, line 91.

(gdb) commands

Type commands for breakpoint(s) 4, one per line.

End with a line saying just "end".

>python print( "key {} val {}".format(gdb.parse_and_eval("key"), gdb.parse_and_eval("val")) )

>c

>end

(gdb)

... but the output is way too verbose, which is why I want dprintf in the first place:

(gdb) c

Continuing.

Thread 1 "SciTE" hit Breakpoint 4, PropSetFile::Set (this=this@entry=0x7fffffffbea0, 

    key="XDG_MENU_PREFIX", val="gnome-") at ./../src/PropSetFile.cxx:91

91  void PropSetFile::Set(std::string_view key, std::string_view val) {

key "XDG_MENU_PREFIX" val "gnome-"



Thread 1 "SciTE" hit Breakpoint 4, PropSetFile::Set (this=this@entry=0x7fffffffbea0, 

    key="KIGITHUB", val="https://github.com/KiCad") at ./../src/PropSetFile.cxx:91

91  void PropSetFile::Set(std::string_view key, std::string_view val) {

key "KIGITHUB" val "https://github.com/KiCad"

...

... so I guess this question is still open...

share|improve this answer

answered Jan 3 at 4:50

sdaausdaau

20.4k28154207

add a comment | 

Your Answer

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1 Answer
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1 Answer
1

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oldest

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active

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votes

0

Here is a workaround using gdb python:

(gdb) break PropSetFile::Set

Breakpoint 4 at 0x555555667700: file ./../src/PropSetFile.cxx, line 91.

(gdb) commands

Type commands for breakpoint(s) 4, one per line.

End with a line saying just "end".

>python print( "key {} val {}".format(gdb.parse_and_eval("key"), gdb.parse_and_eval("val")) )

>c

>end

(gdb)

... but the output is way too verbose, which is why I want dprintf in the first place:

(gdb) c

Continuing.

Thread 1 "SciTE" hit Breakpoint 4, PropSetFile::Set (this=this@entry=0x7fffffffbea0, 

    key="XDG_MENU_PREFIX", val="gnome-") at ./../src/PropSetFile.cxx:91

91  void PropSetFile::Set(std::string_view key, std::string_view val) {

key "XDG_MENU_PREFIX" val "gnome-"



Thread 1 "SciTE" hit Breakpoint 4, PropSetFile::Set (this=this@entry=0x7fffffffbea0, 

    key="KIGITHUB", val="https://github.com/KiCad") at ./../src/PropSetFile.cxx:91

91  void PropSetFile::Set(std::string_view key, std::string_view val) {

key "KIGITHUB" val "https://github.com/KiCad"

...

... so I guess this question is still open...

share|improve this answer

answered Jan 3 at 4:50

sdaausdaau

20.4k28154207

add a comment | 

0

Here is a workaround using gdb python:

(gdb) break PropSetFile::Set

Breakpoint 4 at 0x555555667700: file ./../src/PropSetFile.cxx, line 91.

(gdb) commands

Type commands for breakpoint(s) 4, one per line.

End with a line saying just "end".

>python print( "key {} val {}".format(gdb.parse_and_eval("key"), gdb.parse_and_eval("val")) )

>c

>end

(gdb)

... but the output is way too verbose, which is why I want dprintf in the first place:

(gdb) c

Continuing.

Thread 1 "SciTE" hit Breakpoint 4, PropSetFile::Set (this=this@entry=0x7fffffffbea0, 

    key="XDG_MENU_PREFIX", val="gnome-") at ./../src/PropSetFile.cxx:91

91  void PropSetFile::Set(std::string_view key, std::string_view val) {

key "XDG_MENU_PREFIX" val "gnome-"



Thread 1 "SciTE" hit Breakpoint 4, PropSetFile::Set (this=this@entry=0x7fffffffbea0, 

    key="KIGITHUB", val="https://github.com/KiCad") at ./../src/PropSetFile.cxx:91

91  void PropSetFile::Set(std::string_view key, std::string_view val) {

key "KIGITHUB" val "https://github.com/KiCad"

...

... so I guess this question is still open...

share|improve this answer

answered Jan 3 at 4:50

sdaausdaau

20.4k28154207

add a comment | 

0

0

0

Here is a workaround using gdb python:

(gdb) break PropSetFile::Set

Breakpoint 4 at 0x555555667700: file ./../src/PropSetFile.cxx, line 91.

(gdb) commands

Type commands for breakpoint(s) 4, one per line.

End with a line saying just "end".

>python print( "key {} val {}".format(gdb.parse_and_eval("key"), gdb.parse_and_eval("val")) )

>c

>end

(gdb)

... but the output is way too verbose, which is why I want dprintf in the first place:

(gdb) c

Continuing.

Thread 1 "SciTE" hit Breakpoint 4, PropSetFile::Set (this=this@entry=0x7fffffffbea0, 

    key="XDG_MENU_PREFIX", val="gnome-") at ./../src/PropSetFile.cxx:91

91  void PropSetFile::Set(std::string_view key, std::string_view val) {

key "XDG_MENU_PREFIX" val "gnome-"



Thread 1 "SciTE" hit Breakpoint 4, PropSetFile::Set (this=this@entry=0x7fffffffbea0, 

    key="KIGITHUB", val="https://github.com/KiCad") at ./../src/PropSetFile.cxx:91

91  void PropSetFile::Set(std::string_view key, std::string_view val) {

key "KIGITHUB" val "https://github.com/KiCad"

...

... so I guess this question is still open...

share|improve this answer

answered Jan 3 at 4:50

sdaausdaau

20.4k28154207

Here is a workaround using gdb python:

(gdb) break PropSetFile::Set

Breakpoint 4 at 0x555555667700: file ./../src/PropSetFile.cxx, line 91.

(gdb) commands

Type commands for breakpoint(s) 4, one per line.

End with a line saying just "end".

>python print( "key {} val {}".format(gdb.parse_and_eval("key"), gdb.parse_and_eval("val")) )

>c

>end

(gdb)

... but the output is way too verbose, which is why I want dprintf in the first place:

(gdb) c

Continuing.

Thread 1 "SciTE" hit Breakpoint 4, PropSetFile::Set (this=this@entry=0x7fffffffbea0, 

    key="XDG_MENU_PREFIX", val="gnome-") at ./../src/PropSetFile.cxx:91

91  void PropSetFile::Set(std::string_view key, std::string_view val) {

key "XDG_MENU_PREFIX" val "gnome-"



Thread 1 "SciTE" hit Breakpoint 4, PropSetFile::Set (this=this@entry=0x7fffffffbea0, 

    key="KIGITHUB", val="https://github.com/KiCad") at ./../src/PropSetFile.cxx:91

91  void PropSetFile::Set(std::string_view key, std::string_view val) {

key "KIGITHUB" val "https://github.com/KiCad"

...

... so I guess this question is still open...

share|improve this answer

answered Jan 3 at 4:50

sdaausdaau

20.4k28154207

share|improve this answer

share|improve this answer

answered Jan 3 at 4:50

sdaausdaau

20.4k28154207

answered Jan 3 at 4:50

sdaausdaau

20.4k28154207

answered Jan 3 at 4:50

sdaausdaau

20.4k28154207

20.4k28154207

add a comment | 

add a comment | 

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To learn more, see our tips on writing great answers.

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