The d's

I have looked all over, but I can't seem to figure out where the d's are defined, or are they part of a lib someplace are they macros'.... you may be wondering the in the world I'm talking abou, so here they are.

I won't list them all, but here are is a block of some:

extern char* dStrcat(char *dst, const char *src);
extern char* dStrncat(char* dst, const char* src, dsize_t len);
extern char* dStrcatl(char *dst, dsize_t dstSize, ...);
extern int dStrcmp(const char *str1, const char *str2);
extern int dStricmp(const char *str1, const char *str2);
extern int dStrncmp(const char *str1, const char *str2, dsize_t len);
extern int dStrnicmp(const char *str1, const char *str2, dsize_t len);
extern char* dStrcpy(char *dst, const char *src);
extern char* dStrcpyl(char *dst, dsize_t dstSize, ...);
extern char* dStrncpy(char *dst, const char *src, dsize_t len);
extern dsize_t dStrlen(const char *str);
extern char* dStrupr(char *str);
extern char* dStrlwr(char *str);
extern char* dStrchr(char *str, int c);
extern const char* dStrchr(const char *str, int c);
extern char* dStrrchr(char *str, int c);
extern const char* dStrrchr(const char *str, int c);
extern dsize_t dStrspn(const char *str, const char *set);
extern dsize_t dStrcspn(const char *str, const char *set);

I recognize them of course without the dS, and rather just the s, but I can't for the life of me
figure out where they exist. I get a bunch of link error's reguarding them, I'm not sure what I'm missing.

Any help would be greatly appreciated.