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Hi guys,
I am trying to implement some command-line arguments for my application. I would like to be able to run the program with "Program.exe -w800 -h600" to force the resolution to be displayed at 800*600.
I've come up with this basic code that I would have thought could achieve the goal I had in mind but I get the error
error C2446: '==' : no conversion from 'const char *' to 'int' There is no context in which this conversion is possible
So lpCmdLine is a pointer to a const char, so how do I extract the information I want from it? Wouldn't it have been easier for microsoft to just implement it as an array of char's? 
WINDOW_WIDTH and WINDOW_HEIGHT are both global integers.
for (int n=0; n < (sizeof(lpCmdLine) / sizeof(char)); n++)
{
if(lpCmdLine[n] == "-" && lpCmdLine[n+1] == "w")
{
char w[4];
w[0] = lpCmdLine[n+2];
w[1] = lpCmdLine[n+3];
w[2] = lpCmdLine[n+4];
w[3] = lpCmdLine[n+5];
WINDOW_WIDTH = w[];
}
if(lpCmdLine[n] == "-" && lpCmdLine[n+1] == "h")
{
char h[4];
h[0] = lpCmdLine[n+2];
h[1] = lpCmdLine[n+3];
h[2] = lpCmdLine[n+4];
h[3] = lpCmdLine[n+5];
WINDOW_HEIGHT = h[];
}
}
The solution probably has something to do with some hefty use of pointers
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You should use atoi[^] if you want to convert a string (e.g. "800") into the corresponding integer.
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sorry but I don't think that will work for my purposes
I need to be able to parse the string first for any - signs followed by either a w or h. Once I get that working then I would be able to use atoi to convert the numbers in the string but I can't get to that point using atoi
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Your code has several flaws.
Try
int iLen = _tcslen(lpCmdLine);
for (int i = 0; i < iLen - 2; i++)
{
if ( lpCmdLine[i] == _T('-'))
{
if (lpCmdLine[i+1] == _T('h'))
{
WINDOW_HEIGHT = _tstoi(&(lpCmdLine[i+2]));
}
else if (lpCmdLine[i+1] == _T('w'))
{
WINDOW_WIDTH = _tstoi(&(lpCmdLine[i+2]));
}
}
}
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
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It took me a few minutes to understand your code (had to search through all the help files for all that stuff I've never seen before)
It looks like it should work.
But it doesnt
error C2664: 'wcslen' : cannot convert parameter 1 from 'LPSTR' to 'const wchar_t *'
Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
error C2664: '_wtoi' : cannot convert parameter 1 from 'CHAR *' to 'const wchar_t *'
Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
error C2664: '_wtoi' : cannot convert parameter 1 from 'CHAR *' to 'const wchar_t *'
Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast
And could you please give me some hints as to why my code is flawed? I was already aware there was something wrong with it, hence the reason it doesn't work.
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OK. These errors arise because the LPSTR nature of lpCmdLine. Use:
int iLen = strlen(lpCmdLine);
for (int i = 0; i < iLen - 2; i++)
{
if ( lpCmdLine[i] == '-')
{
if (lpCmdLine[i+1] == 'h')
{
WINDOW_HEIGHT = atoi(&(lpCmdLine[i+2]));
}
else if (lpCmdLine[i+1] =='w')
{
WINDOW_WIDTH = atoi(&(lpCmdLine[i+2]));
}
}
}
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
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thankyou, your code works flawlessly. 
Bloody legend :P
Now, may we discuss the bad things I did in my original snippet so that I may learn from it in the future? That would be nice
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Sauce! wrote: Now, may we discuss the bad things I did in my original snippet so that I may learn from it in the future? That would be nice
Your original code:
for (int n=0; n < (sizeof(lpCmdLine) / sizeof(char)); n++)
{
if(lpCmdLine[n] == "-" && lpCmdLine[n+1] == "w")
{
char w[4];
w[0] = lpCmdLine[n+2];
w[1] = lpCmdLine[n+3];
w[2] = lpCmdLine[n+4];
w[3] = lpCmdLine[n+5];
WINDOW_WIDTH = w[];
}
if(lpCmdLine[n] == "-" && lpCmdLine[n+1] == "h")
{
char h[4];
h[0] = lpCmdLine[n+2];
h[1] = lpCmdLine[n+3];
h[2] = lpCmdLine[n+4];
h[3] = lpCmdLine[n+5];
WINDOW_HEIGHT = h[];
}
}
1. sizeof(lpCmdLine) = sizeof(LPSTR) = 4 (on 32 bit systems). You should use strlen(lpCmdLine) instead.
2. Since the code inside the loop accesses lpCmdLine[n+5], the loop itself cannot run on the whole lpCmdLine's range available.
So the loop controlling condition should be (n < strlen(lpCmdLine) - 5) to
prevent buffer overrun.
3. You wrote your own version of atoi, but it is wrong: suppose pCmdLine[0] to pCmdLine[3] containing the right input for the number, the (brute force and simplified) code for a atoi-like function may be
int value = 0;
value = pCmdLine[0]-'0';
value *= 10;
value += pCmdLine[1]-'0';
value *= 10;
value += pCmdLine[2]-'0';
value *= 10;
value += pCmdLine[3]-'0';
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
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1) Huh, missed that one completely. Probably could have been avoided if I could find some better documentation on the exact data-type and format of lpCmdLine. Microsoft's documentation was pretty poor.
2) thanks, I was wondering why you subtracted 2 from iLen in your example. I thought to myself "yeah, it's technically correct, but you don't need to do it" (what a stupid thing to think!) I didn't even think about preventing buffer overrun.
3) I'm not sure what you're getting at here...
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Sauce! wrote: 3) I'm not sure what you're getting at here...
Well, suppose:
lpCmdLine = "-w800";
this really means
lpCmdLine[0] = '-';
lpCmdLine[1] = 'w';
lpCmdLine[2] = '8';
lpCmdLine[3] = '0';
lpCmdLine[4] = '0';
Consider lpCmdLine[2] = '8'. Here lpCmdLine[2] is a char variable holding the ASCII value of the character '8' (that is 56 decimal). If you write
int iFirstDigit = lpCmdLine[2];
then you make a mistake, because iFirstDigit will contain 56 instead of 8. On the other hand, writing
int iFirstDigit = lpCmdLine[2] - '0';
you get the expected value (in a rather portable way), since numbers are ordered in the ASCII encoding following their natural (ordinal!) sequence, hence
lpCmdLine[2] - '0' = 56 - 48 = 8.
Now, suppose you make the same for the following digits, obtaining
iFirstDigit = 8;
iSecondDigit = 0;
iThirdDigit = 0;
to finally build the number you have to exploint the base 10 positional numbering system, i.e. poorly speaking:
int iNumber = iFrstDigit * 100 + iSecondDigit * 10 + iThirdDigit;
I made the above in a incremental way on previously posted code.
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
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You're so clever :]
Thankyou very much for your help. You've been quite informative
I've never fully understood converting from char's to int's, but you've cleared it all up for me
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Sauce! wrote: You're so clever :]
Thank you. 
Sauce! wrote: Thankyou very much for your help. You've been quite informative
I've never fully understood converting from char's to int's, but you've cleared it all up for me
You're welcome.
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
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Sauce! wrote: if(lpCmdLine[n] == "-" && lpCmdLine[n+1] == "w")
...
if(lpCmdLine[n] == "-" && lpCmdLine[n+1] == "h")
lpCmdLine[n] is a single character, yet you are comparing to an array of characters (even though there is only one character present). You should use single quotes instead, like:
if (lpCmdLine[n] == '-' && lpCmdLine[n+1] == 'w')
"Love people and use things, not love things and use people." - Unknown
"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne
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How to verify that calling process has read access to the specified range of memory in vista. Earlier IsBadReadPtr and IsBadWritePtr could be used. But it is not suggestible by Microsoft. Can I know any other alternate method to verify that calling process has access to memory
Thanks,
Venkat
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In almost all cases the professional thing to do is crash. Why are you so insistent on implementing what is almost certainly a bad idea? We’ve had this discussion before. If you can give a compelling reason why your application is an exception I’ll give you some pointers, but I’m reluctant to be a part of the spread of bad programming practices.
Steve
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I assume you just voted my reply down. If so, that's all well and good, but it doesn't change the facts. Again, see the following expert opinions on this issue:
Raymond Chen[^]: "You should crash."
Larry Osterman[^]
Steve
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Hi friends,
The following code is giving the above error.
#include windows.h ;
#import msxml.dll ;
int main(int, char*[])
{
return 0;
} on vista.
I got a solution in msdn forums to replace the msxml.dll with msxml.tlb .Still i am getting the same error saying "Cannot open type library file: 'msxml.tlb':"
(http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=365059&SiteID=1[^]
Can someone tell me the reason for this.
Thanks in advance.
Appu..
"Never explain yourself to anyone.
Because the person who likes you does n't need it.
And the person who dislikes you won't believe it."
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Documentation for #import can be found here[^]. The following table is a quote from the section entitled "Search Order for filename":
| Syntax form | Action | | Quoted form | Instructs the preprocessor to look for type library files first in the directory of the file that contains the #import statement, and then in the directories of whatever files that include (#include) that file. The preprocessor then searches along the paths shown below. | | Angle-bracket form | Instructs the preprocessor to search for type library files along the following paths:
1. The PATH environment variable path list
2. The LIB environment variable path list
3. The path specified by the /I (additional include directories) compiler option
|
This should be enough for you to fix the problem.
Steve
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I have to write code for enabling DHCP using win32 API.can anybody help?I don't want WMI functions for this.Thanks....
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Hellow
I made owner draw list view.
On the viusal studio emulator( Window Mobile 6 SDK ), it work well. I receive WM_MEASUREITEM & WM_DRAWITEM .
But on the device, No WM_DRAWITEM message come after I receive WM_MEASUREITEM,
Some part of my code is below
case WM_MEASUREITEM:
//OnListViewMeasureItem(g_hwndListView,(int)wParam,(LPMEASUREITEMSTRUCT)lParam);
lpmis=(LPMEASUREITEMSTRUCT)lParam;
lpmis->itemWidth=100;
lpmis->itemHeight=20;
return TRUE;
case WM_DRAWITEM:
OnListViewDrawItem((LPDRAWITEMSTRUCT) lParam);
return 0;
What's long with me?
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When I compile a C project in VC++ .Net, this error is coming in a standard vc++ file "cerrno":
" error C2143: syntax error : missing '{' before ':'"
The code is as follows:
#if _GLOBAL_USING
_STD_BEGIN
#ifndef errno
using ::errno;
#endif /* errno */
How to solve this error?
Am I missing any SP for vc++ or something else?
Regards,
Suman
--
"Programming is an art that fights back!"
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rp_suman wrote: #if _GLOBAL_USING_STD_BEGIN #ifndef errnousing ::errno; // <-- Compiler point error here #endif /* errno */
please check setting of VC++ .net complier, might be it using path of older version!
"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow
Never mind - my own stupidity is the source of every "problem" - Mixture
cheers,
Alok Gupta
VC Forum Q&A :- I/ IV
Support CRY- Child Relief and You/xml>
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Hi,
Thanks for your help, but I was available of original compiler this evening and finished compile on that!
But I will check your idea, when I will again work with VC++ for the same program.
Regards,
Suman
--
"Programming is an art that fights back!"
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How to check the path of the compiler?
In the new system where error happened, there was no VC++ .Net 2003 Toolkit installed.
I installed it now. Do I need to set this path to somewhere in compiler?
Regards,
Suman
--
"Programming is an art that fights back!"
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