CODEWITHSUNDEEP
unicodedriverstring-literalswchar
Louie
Louie

Reputation: 11

How do I initialize a WCHAR string from an ascii string that is #defined. L prefix is not included

In Windows driver C code, I need to set a WCHAR array to a string that is #defined in a header file. The header file specifies an ascii string. It does not specify the L prefix for the string.

// In the header file
#define VERS_STR "3.2.4"

// In the C file, none of the following work
WCHAR awcStr[] = LVERS_STR;    // Compiler Error: Treated as one name
WCHAR awcStr[] = L VERS_STR;   // Compiler Error: L is unknown
WCHAR awcStr[] = L(VERS_STR);  // Compiler Error
WCHAR awcStr[] = L"3.2.4";     // Compiles and runs, but I must use #define instead

I would call a conversion routine on the #define, but I can't find one that I can call from a Windows driver using C code.

Upvotes: 0

Views: 233

Answers (1)

Mark Tolonen
Mark Tolonen

Reputation: 177901

A WIDE macro might exist, but I’m not where I can check easily, but this sequence implements it:

#define WIDE2(x) L##x
#define WIDE1(x) WIDE2(x)
#define WIDE(x) WIDE1(x)

Due to how macros work, WIDE1 will expand your macro, and WIDE2 will add the L with the concatenation macro operator. Just call WIDE(VERS_STR).

Upvotes: 2

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