CODEWITHSUNDEEP
cwinapiapi
dikidera
dikidera

Reputation: 2043

How do i modify this LPSTR?

Let's suppose for a moment i have this variable

LPTSTR cmdArgs = "D:\\path\my.exe -user blah PLATFORM=0 DEVICE=0 -k poclbm VECTORS BFI_INT WORKSIZE=128 AGGRESSION=7";

Notice where it says DEVICE=0 well, in my case it could be DEVICE=1 or DEVICE=2 etc.

That would mean that, that string must be dynamic. I am going to pass to a function the number which would should come after DEVICE= however, i have no idea how to add it to the cmdArgs variable.

I was thinking of using sprintf and do DEVICE=%d, but i've no idea if i can cast a char variable(which will contain the formatted string) to an LPSTR

Upvotes: 0

Views: 2223

Answers (3)

Praetorian
Praetorian

Reputation: 109189

An LPSTR is a typedef for a char *. You can use sprintf for inserting the device number into the string.

char cmdArgs[1000];
int deviceNum = 1;
sprintf( cmdArgs, "D:\\path\\my.exe -user blah PLATFORM=0 DEVICE=%d -k poclbm VECTORS BFI_INT WORKSIZE=128 AGGRESSION=7", deviceNum );

EDIT:
Since the code snippet shows an LPTSTR you may want to use TCHAR routines instead of sprintf. LPTSTR is typedef'd as whcar_t * when _UNICODE preprocessor symbol is defined, and char * if that symbol is not defined or _MBCS is defined.

TCHAR cmdArgs[1000];
int deviceNum = 1;
_stprintf( cmdArgs, _T(""D:\\path\\my.exe -user blah PLATFORM=0 DEVICE=%d -k poclbm VECTORS BFI_INT WORKSIZE=128 AGGRESSION=7"), deviceNum );

Upvotes: 2

blindauer
blindauer

Reputation: 394

Your summary says LPSTR, but your code block says LPTSTR. These (might) be different things, depending on if you're building for Unicode or not.

In unicode builds, LPTSTR is a wchar_t*. In non-unicode, LPTSTR is char*. LPSTR is char* in both cases.

winnt.h has these typedefs (these aren't the literal typedef's, I've kinda paraphrased them here):

typedef char CHAR;
typedef CHAR *LPSTR;

typedef wchar_t WCHAR;
typedef WCHAR *LPWSTR;

#ifdef UNICODE
typedef LPWSTR LPTSTR;
#else
typedef LPSTR LPTSTR;
#endif

If you're building non-Unicode, sprintf with %d will do what you want, as specified by others here.

Upvotes: 1

drdwilcox
drdwilcox

Reputation: 3951

Why not use %s, since you have a char *.

Upvotes: 0

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