Accessing MONITORINFOEX values in Visual C++
-1
I'm perplexed trying to retrieve MONITORINFOEX values. I tried:
typedef struct tagMONITORINFO
DWORD cbSize;
RECT rcMonitor;
RECT rcWork;
DWORD dwFlags;
MONITORINFO, *LPMONITORINFO;
typedef struct tagMONITORINFOEX
CHAR szDevice[CCHDEVICENAME];
MONITORINFO tagMONITORINFO;
MONITORINFOEX, *LPMONITORINFOEX;
MONITORINFOEX miea;
miea.tagMONITORINFO.cbSize = sizeof(MONITORINFOEX);
GetMonitorInfo(hMonitor, (&miea));
to no avail. I modified the last line to:
GetMonitorInfo(hMonitor, ((LPMONITORINFO) &miea));
again, no luck. I get compiler messages about the 2nd parameter of GetMonitorInfo.
Perhaps my recent inexperience with C++ is showing.
Thanks in advance for any help you may provide.
c++ winapi
asked Nov 13 '18 at 13:18
John-L_.John-L_.
66
|
show 1 more comment
-1
I'm perplexed trying to retrieve MONITORINFOEX values. I tried:
typedef struct tagMONITORINFO
DWORD cbSize;
RECT rcMonitor;
RECT rcWork;
DWORD dwFlags;
MONITORINFO, *LPMONITORINFO;
typedef struct tagMONITORINFOEX
CHAR szDevice[CCHDEVICENAME];
MONITORINFO tagMONITORINFO;
MONITORINFOEX, *LPMONITORINFOEX;
MONITORINFOEX miea;
miea.tagMONITORINFO.cbSize = sizeof(MONITORINFOEX);
GetMonitorInfo(hMonitor, (&miea));
to no avail. I modified the last line to:
GetMonitorInfo(hMonitor, ((LPMONITORINFO) &miea));
again, no luck. I get compiler messages about the 2nd parameter of GetMonitorInfo.
Perhaps my recent inexperience with C++ is showing.
Thanks in advance for any help you may provide.
c++ winapi
asked Nov 13 '18 at 13:18
John-L_.John-L_.
66
1
Why do you redefine the structures? Why not include the proper Windows header files and use the standard structures? And what is your problem with the code you show? Do you get build errors? Runtime errors or crashes? Invalid results?
– Some programmer dude
Nov 13 '18 at 13:20
I get compiler messages about the 2nd parameter of GetMonitorInfo. Add the error messages to the question.
– Johnny Mopp
Nov 13 '18 at 13:24
your definition ofMONITORINFOEXis wrong. and anyway - it defined in MultiMon.h -struct tagMONITORINFOEXA : public tagMONITORINFO CHAR szDevice[CCHDEVICENAME]; MONITORINFOEXA, *LPMONITORINFOEXA;
– RbMm
Nov 13 '18 at 13:32
@som: It's only a redefinition, if you actually include the header files that define the structures. While common, there are reasons why you'd want to define those structures yourself. A library may not want to#include <Windows.h>, and rather define what it needs. C++/WinRT recently removed the dependency on Windows.h, for example.
– IInspectable
Nov 13 '18 at 17:04
@IInspectable It would be a redefinition if the structures were a byte-by-byte, character by character, exact duplicate. Otherwise it's undefined behavior as it breaks the one definition rule. And in this case it apparently isn't exact duplicates.
– Some programmer dude
Nov 13 '18 at 17:28
|
show 1 more comment
-1
-1
-1
I'm perplexed trying to retrieve MONITORINFOEX values. I tried:
typedef struct tagMONITORINFO
DWORD cbSize;
RECT rcMonitor;
RECT rcWork;
DWORD dwFlags;
MONITORINFO, *LPMONITORINFO;
typedef struct tagMONITORINFOEX
CHAR szDevice[CCHDEVICENAME];
MONITORINFO tagMONITORINFO;
MONITORINFOEX, *LPMONITORINFOEX;
MONITORINFOEX miea;
miea.tagMONITORINFO.cbSize = sizeof(MONITORINFOEX);
GetMonitorInfo(hMonitor, (&miea));
to no avail. I modified the last line to:
GetMonitorInfo(hMonitor, ((LPMONITORINFO) &miea));
again, no luck. I get compiler messages about the 2nd parameter of GetMonitorInfo.
Perhaps my recent inexperience with C++ is showing.
Thanks in advance for any help you may provide.
c++ winapi
asked Nov 13 '18 at 13:18
John-L_.John-L_.
66
I'm perplexed trying to retrieve MONITORINFOEX values. I tried:
typedef struct tagMONITORINFO
DWORD cbSize;
RECT rcMonitor;
RECT rcWork;
DWORD dwFlags;
MONITORINFO, *LPMONITORINFO;
typedef struct tagMONITORINFOEX
CHAR szDevice[CCHDEVICENAME];
MONITORINFO tagMONITORINFO;
MONITORINFOEX, *LPMONITORINFOEX;
MONITORINFOEX miea;
miea.tagMONITORINFO.cbSize = sizeof(MONITORINFOEX);
GetMonitorInfo(hMonitor, (&miea));
to no avail. I modified the last line to:
GetMonitorInfo(hMonitor, ((LPMONITORINFO) &miea));
again, no luck. I get compiler messages about the 2nd parameter of GetMonitorInfo.
Perhaps my recent inexperience with C++ is showing.
Thanks in advance for any help you may provide.
c++ winapi
c++ winapi
asked Nov 13 '18 at 13:18
John-L_.John-L_.
66
asked Nov 13 '18 at 13:18
John-L_.John-L_.
66
asked Nov 13 '18 at 13:18
John-L_.John-L_.
66
asked Nov 13 '18 at 13:18
John-L_.John-L_.
66
asked Nov 13 '18 at 13:18
John-L_.John-L_.
66
66
1
Why do you redefine the structures? Why not include the proper Windows header files and use the standard structures? And what is your problem with the code you show? Do you get build errors? Runtime errors or crashes? Invalid results?
– Some programmer dude
Nov 13 '18 at 13:20
I get compiler messages about the 2nd parameter of GetMonitorInfo. Add the error messages to the question.
– Johnny Mopp
Nov 13 '18 at 13:24
your definition ofMONITORINFOEXis wrong. and anyway - it defined in MultiMon.h -struct tagMONITORINFOEXA : public tagMONITORINFO CHAR szDevice[CCHDEVICENAME]; MONITORINFOEXA, *LPMONITORINFOEXA;
– RbMm
Nov 13 '18 at 13:32
@som: It's only a redefinition, if you actually include the header files that define the structures. While common, there are reasons why you'd want to define those structures yourself. A library may not want to#include <Windows.h>, and rather define what it needs. C++/WinRT recently removed the dependency on Windows.h, for example.
– IInspectable
Nov 13 '18 at 17:04
@IInspectable It would be a redefinition if the structures were a byte-by-byte, character by character, exact duplicate. Otherwise it's undefined behavior as it breaks the one definition rule. And in this case it apparently isn't exact duplicates.
– Some programmer dude
Nov 13 '18 at 17:28
|
show 1 more comment
1
Why do you redefine the structures? Why not include the proper Windows header files and use the standard structures? And what is your problem with the code you show? Do you get build errors? Runtime errors or crashes? Invalid results?
– Some programmer dude
Nov 13 '18 at 13:20
I get compiler messages about the 2nd parameter of GetMonitorInfo. Add the error messages to the question.
– Johnny Mopp
Nov 13 '18 at 13:24
your definition ofMONITORINFOEXis wrong. and anyway - it defined in MultiMon.h -struct tagMONITORINFOEXA : public tagMONITORINFO CHAR szDevice[CCHDEVICENAME]; MONITORINFOEXA, *LPMONITORINFOEXA;
– RbMm
Nov 13 '18 at 13:32
@som: It's only a redefinition, if you actually include the header files that define the structures. While common, there are reasons why you'd want to define those structures yourself. A library may not want to#include <Windows.h>, and rather define what it needs. C++/WinRT recently removed the dependency on Windows.h, for example.
– IInspectable
Nov 13 '18 at 17:04
@IInspectable It would be a redefinition if the structures were a byte-by-byte, character by character, exact duplicate. Otherwise it's undefined behavior as it breaks the one definition rule. And in this case it apparently isn't exact duplicates.
– Some programmer dude
Nov 13 '18 at 17:28
1
1
Why do you redefine the structures? Why not include the proper Windows header files and use the standard structures? And what is your problem with the code you show? Do you get build errors? Runtime errors or crashes? Invalid results?
– Some programmer dude
Nov 13 '18 at 13:20
Why do you redefine the structures? Why not include the proper Windows header files and use the standard structures? And what is your problem with the code you show? Do you get build errors? Runtime errors or crashes? Invalid results?
– Some programmer dude
Nov 13 '18 at 13:20
I get compiler messages about the 2nd parameter of GetMonitorInfo. Add the error messages to the question.
– Johnny Mopp
Nov 13 '18 at 13:24
I get compiler messages about the 2nd parameter of GetMonitorInfo. Add the error messages to the question.
– Johnny Mopp
Nov 13 '18 at 13:24
your definition of
MONITORINFOEX is wrong. and anyway - it defined in MultiMon.h - struct tagMONITORINFOEXA : public tagMONITORINFO CHAR szDevice[CCHDEVICENAME]; MONITORINFOEXA, *LPMONITORINFOEXA;– RbMm
Nov 13 '18 at 13:32
your definition of
MONITORINFOEX is wrong. and anyway - it defined in MultiMon.h - struct tagMONITORINFOEXA : public tagMONITORINFO CHAR szDevice[CCHDEVICENAME]; MONITORINFOEXA, *LPMONITORINFOEXA;– RbMm
Nov 13 '18 at 13:32
@som: It's only a redefinition, if you actually include the header files that define the structures. While common, there are reasons why you'd want to define those structures yourself. A library may not want to
#include <Windows.h>, and rather define what it needs. C++/WinRT recently removed the dependency on Windows.h, for example.– IInspectable
Nov 13 '18 at 17:04
@som: It's only a redefinition, if you actually include the header files that define the structures. While common, there are reasons why you'd want to define those structures yourself. A library may not want to
#include <Windows.h>, and rather define what it needs. C++/WinRT recently removed the dependency on Windows.h, for example.– IInspectable
Nov 13 '18 at 17:04
@IInspectable It would be a redefinition if the structures were a byte-by-byte, character by character, exact duplicate. Otherwise it's undefined behavior as it breaks the one definition rule. And in this case it apparently isn't exact duplicates.
– Some programmer dude
Nov 13 '18 at 17:28
@IInspectable It would be a redefinition if the structures were a byte-by-byte, character by character, exact duplicate. Otherwise it's undefined behavior as it breaks the one definition rule. And in this case it apparently isn't exact duplicates.
– Some programmer dude
Nov 13 '18 at 17:28
|
show 1 more comment
1 Answer
1
active
oldest
votes
3
In the code you have shown you try to define structs that are part of WinAPI yourself. Don't do that, there is no need to. Include the appropriate header files instead.
Simple sample:
#include <cstdlib>
#include <iostream>
#include <windows.h>
int main()
// just a cheap way to get a handle
auto monitor MonitorFromWindow(GetConsoleWindow(), MONITOR_DEFAULTTONEAREST) ;
MONITORINFOEXW miex sizeof miex ; // set cbSize member
if (!GetMonitorInfoW(monitor, &miex))
std::cerr << "GetMonitorInfo() failed :(nn";
return EXIT_FAILURE;
std::wcout << miex.szDevice << ": "
<< miex.rcMonitor.right - miex.rcMonitor.left << " x "
<< miex.rcMonitor.bottom - miex.rcMonitor.top << 'n';
Sample output:
\.DISPLAY1: 2560 x 1440
answered Nov 13 '18 at 13:30
SwordfishSwordfish
9,19511335
1
not needstatic_cast<LPMONITORINFO>(&miex)can simply use&miexbecauseMONITORINFOEXW : public MONITORINFO
– RbMm
Nov 13 '18 at 13:40
@RbMm Right. Was a little surprised though since most WinAPI structs don't use inheritance.
– Swordfish
Nov 13 '18 at 13:45
The winapi targets the C language, not C++. I think the core advice is that the OP must not declare the structs by himself, that's not going to end well since these identifiers are macros and not structs. Be sure to point that out.
– Hans Passant
Nov 13 '18 at 14:02
@HansPassant "The winapi targets the C language, not C++." thats why i was surprised.
– Swordfish
Nov 13 '18 at 14:06
MONITORINFOEXderiving fromMONITORINFOis wrapped in a#ifdef __cpluspluspreprocessor guard. The C implementation uses composition, whereMONITORINFOis the first member ofMONITORINFOEX. The entirety of the Windows API (and Windows Runtime) is still exposed as a C interface, with occasional convenience wrappers and declarations in C++.
– IInspectable
Nov 13 '18 at 17:26
add a comment |
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1 Answer
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1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
3
In the code you have shown you try to define structs that are part of WinAPI yourself. Don't do that, there is no need to. Include the appropriate header files instead.
Simple sample:
#include <cstdlib>
#include <iostream>
#include <windows.h>
int main()
// just a cheap way to get a handle
auto monitor MonitorFromWindow(GetConsoleWindow(), MONITOR_DEFAULTTONEAREST) ;
MONITORINFOEXW miex sizeof miex ; // set cbSize member
if (!GetMonitorInfoW(monitor, &miex))
std::cerr << "GetMonitorInfo() failed :(nn";
return EXIT_FAILURE;
std::wcout << miex.szDevice << ": "
<< miex.rcMonitor.right - miex.rcMonitor.left << " x "
<< miex.rcMonitor.bottom - miex.rcMonitor.top << 'n';
Sample output:
\.DISPLAY1: 2560 x 1440
answered Nov 13 '18 at 13:30
SwordfishSwordfish
9,19511335
1
not needstatic_cast<LPMONITORINFO>(&miex)can simply use&miexbecauseMONITORINFOEXW : public MONITORINFO
– RbMm
Nov 13 '18 at 13:40
@RbMm Right. Was a little surprised though since most WinAPI structs don't use inheritance.
– Swordfish
Nov 13 '18 at 13:45
The winapi targets the C language, not C++. I think the core advice is that the OP must not declare the structs by himself, that's not going to end well since these identifiers are macros and not structs. Be sure to point that out.
– Hans Passant
Nov 13 '18 at 14:02
@HansPassant "The winapi targets the C language, not C++." thats why i was surprised.
– Swordfish
Nov 13 '18 at 14:06
MONITORINFOEXderiving fromMONITORINFOis wrapped in a#ifdef __cpluspluspreprocessor guard. The C implementation uses composition, whereMONITORINFOis the first member ofMONITORINFOEX. The entirety of the Windows API (and Windows Runtime) is still exposed as a C interface, with occasional convenience wrappers and declarations in C++.
– IInspectable
Nov 13 '18 at 17:26
add a comment |
3
In the code you have shown you try to define structs that are part of WinAPI yourself. Don't do that, there is no need to. Include the appropriate header files instead.
Simple sample:
#include <cstdlib>
#include <iostream>
#include <windows.h>
int main()
// just a cheap way to get a handle
auto monitor MonitorFromWindow(GetConsoleWindow(), MONITOR_DEFAULTTONEAREST) ;
MONITORINFOEXW miex sizeof miex ; // set cbSize member
if (!GetMonitorInfoW(monitor, &miex))
std::cerr << "GetMonitorInfo() failed :(nn";
return EXIT_FAILURE;
std::wcout << miex.szDevice << ": "
<< miex.rcMonitor.right - miex.rcMonitor.left << " x "
<< miex.rcMonitor.bottom - miex.rcMonitor.top << 'n';
Sample output:
\.DISPLAY1: 2560 x 1440
answered Nov 13 '18 at 13:30
SwordfishSwordfish
9,19511335
1
not needstatic_cast<LPMONITORINFO>(&miex)can simply use&miexbecauseMONITORINFOEXW : public MONITORINFO
– RbMm
Nov 13 '18 at 13:40
@RbMm Right. Was a little surprised though since most WinAPI structs don't use inheritance.
– Swordfish
Nov 13 '18 at 13:45
The winapi targets the C language, not C++. I think the core advice is that the OP must not declare the structs by himself, that's not going to end well since these identifiers are macros and not structs. Be sure to point that out.
– Hans Passant
Nov 13 '18 at 14:02
@HansPassant "The winapi targets the C language, not C++." thats why i was surprised.
– Swordfish
Nov 13 '18 at 14:06
MONITORINFOEXderiving fromMONITORINFOis wrapped in a#ifdef __cpluspluspreprocessor guard. The C implementation uses composition, whereMONITORINFOis the first member ofMONITORINFOEX. The entirety of the Windows API (and Windows Runtime) is still exposed as a C interface, with occasional convenience wrappers and declarations in C++.
– IInspectable
Nov 13 '18 at 17:26
add a comment |
3
3
3
In the code you have shown you try to define structs that are part of WinAPI yourself. Don't do that, there is no need to. Include the appropriate header files instead.
Simple sample:
#include <cstdlib>
#include <iostream>
#include <windows.h>
int main()
// just a cheap way to get a handle
auto monitor MonitorFromWindow(GetConsoleWindow(), MONITOR_DEFAULTTONEAREST) ;
MONITORINFOEXW miex sizeof miex ; // set cbSize member
if (!GetMonitorInfoW(monitor, &miex))
std::cerr << "GetMonitorInfo() failed :(nn";
return EXIT_FAILURE;
std::wcout << miex.szDevice << ": "
<< miex.rcMonitor.right - miex.rcMonitor.left << " x "
<< miex.rcMonitor.bottom - miex.rcMonitor.top << 'n';
Sample output:
\.DISPLAY1: 2560 x 1440
answered Nov 13 '18 at 13:30
SwordfishSwordfish
9,19511335
In the code you have shown you try to define structs that are part of WinAPI yourself. Don't do that, there is no need to. Include the appropriate header files instead.
Simple sample:
#include <cstdlib>
#include <iostream>
#include <windows.h>
int main()
// just a cheap way to get a handle
auto monitor MonitorFromWindow(GetConsoleWindow(), MONITOR_DEFAULTTONEAREST) ;
MONITORINFOEXW miex sizeof miex ; // set cbSize member
if (!GetMonitorInfoW(monitor, &miex))
std::cerr << "GetMonitorInfo() failed :(nn";
return EXIT_FAILURE;
std::wcout << miex.szDevice << ": "
<< miex.rcMonitor.right - miex.rcMonitor.left << " x "
<< miex.rcMonitor.bottom - miex.rcMonitor.top << 'n';
Sample output:
\.DISPLAY1: 2560 x 1440
answered Nov 13 '18 at 13:30
SwordfishSwordfish
9,19511335
edited Nov 13 '18 at 14:05
answered Nov 13 '18 at 13:30
SwordfishSwordfish
9,19511335
answered Nov 13 '18 at 13:30
SwordfishSwordfish
9,19511335
answered Nov 13 '18 at 13:30
SwordfishSwordfish
9,19511335
9,19511335
1
not needstatic_cast<LPMONITORINFO>(&miex)can simply use&miexbecauseMONITORINFOEXW : public MONITORINFO
– RbMm
Nov 13 '18 at 13:40
@RbMm Right. Was a little surprised though since most WinAPI structs don't use inheritance.
– Swordfish
Nov 13 '18 at 13:45
The winapi targets the C language, not C++. I think the core advice is that the OP must not declare the structs by himself, that's not going to end well since these identifiers are macros and not structs. Be sure to point that out.
– Hans Passant
Nov 13 '18 at 14:02
@HansPassant "The winapi targets the C language, not C++." thats why i was surprised.
– Swordfish
Nov 13 '18 at 14:06
MONITORINFOEXderiving fromMONITORINFOis wrapped in a#ifdef __cpluspluspreprocessor guard. The C implementation uses composition, whereMONITORINFOis the first member ofMONITORINFOEX. The entirety of the Windows API (and Windows Runtime) is still exposed as a C interface, with occasional convenience wrappers and declarations in C++.
– IInspectable
Nov 13 '18 at 17:26
add a comment |
1
not needstatic_cast<LPMONITORINFO>(&miex)can simply use&miexbecauseMONITORINFOEXW : public MONITORINFO
– RbMm
Nov 13 '18 at 13:40
@RbMm Right. Was a little surprised though since most WinAPI structs don't use inheritance.
– Swordfish
Nov 13 '18 at 13:45
The winapi targets the C language, not C++. I think the core advice is that the OP must not declare the structs by himself, that's not going to end well since these identifiers are macros and not structs. Be sure to point that out.
– Hans Passant
Nov 13 '18 at 14:02
@HansPassant "The winapi targets the C language, not C++." thats why i was surprised.
– Swordfish
Nov 13 '18 at 14:06
MONITORINFOEXderiving fromMONITORINFOis wrapped in a#ifdef __cpluspluspreprocessor guard. The C implementation uses composition, whereMONITORINFOis the first member ofMONITORINFOEX. The entirety of the Windows API (and Windows Runtime) is still exposed as a C interface, with occasional convenience wrappers and declarations in C++.
– IInspectable
Nov 13 '18 at 17:26
1
1
not need
static_cast<LPMONITORINFO>(&miex) can simply use &miex because MONITORINFOEXW : public MONITORINFO– RbMm
Nov 13 '18 at 13:40
not need
static_cast<LPMONITORINFO>(&miex) can simply use &miex because MONITORINFOEXW : public MONITORINFO– RbMm
Nov 13 '18 at 13:40
@RbMm Right. Was a little surprised though since most WinAPI structs don't use inheritance.
– Swordfish
Nov 13 '18 at 13:45
@RbMm Right. Was a little surprised though since most WinAPI structs don't use inheritance.
– Swordfish
Nov 13 '18 at 13:45
The winapi targets the C language, not C++. I think the core advice is that the OP must not declare the structs by himself, that's not going to end well since these identifiers are macros and not structs. Be sure to point that out.
– Hans Passant
Nov 13 '18 at 14:02
The winapi targets the C language, not C++. I think the core advice is that the OP must not declare the structs by himself, that's not going to end well since these identifiers are macros and not structs. Be sure to point that out.
– Hans Passant
Nov 13 '18 at 14:02
@HansPassant "The winapi targets the C language, not C++." thats why i was surprised.
– Swordfish
Nov 13 '18 at 14:06
@HansPassant "The winapi targets the C language, not C++." thats why i was surprised.
– Swordfish
Nov 13 '18 at 14:06
MONITORINFOEX deriving from MONITORINFO is wrapped in a #ifdef __cplusplus preprocessor guard. The C implementation uses composition, where MONITORINFO is the first member of MONITORINFOEX. The entirety of the Windows API (and Windows Runtime) is still exposed as a C interface, with occasional convenience wrappers and declarations in C++.– IInspectable
Nov 13 '18 at 17:26
MONITORINFOEX deriving from MONITORINFO is wrapped in a #ifdef __cplusplus preprocessor guard. The C implementation uses composition, where MONITORINFO is the first member of MONITORINFOEX. The entirety of the Windows API (and Windows Runtime) is still exposed as a C interface, with occasional convenience wrappers and declarations in C++.– IInspectable
Nov 13 '18 at 17:26
add a comment |
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1
Why do you redefine the structures? Why not include the proper Windows header files and use the standard structures? And what is your problem with the code you show? Do you get build errors? Runtime errors or crashes? Invalid results?
– Some programmer dude
Nov 13 '18 at 13:20
I get compiler messages about the 2nd parameter of GetMonitorInfo. Add the error messages to the question.
– Johnny Mopp
Nov 13 '18 at 13:24
your definition of
MONITORINFOEXis wrong. and anyway - it defined in MultiMon.h -struct tagMONITORINFOEXA : public tagMONITORINFO CHAR szDevice[CCHDEVICENAME]; MONITORINFOEXA, *LPMONITORINFOEXA;– RbMm
Nov 13 '18 at 13:32
@som: It's only a redefinition, if you actually include the header files that define the structures. While common, there are reasons why you'd want to define those structures yourself. A library may not want to
#include <Windows.h>, and rather define what it needs. C++/WinRT recently removed the dependency on Windows.h, for example.– IInspectable
Nov 13 '18 at 17:04
@IInspectable It would be a redefinition if the structures were a byte-by-byte, character by character, exact duplicate. Otherwise it's undefined behavior as it breaks the one definition rule. And in this case it apparently isn't exact duplicates.
– Some programmer dude
Nov 13 '18 at 17:28