| Diagnostics < assert.h > | Shell | DXE | PEI |
| void _wassert (const wchar_t *,const wchar_t *,unsigned) | C90, MSFT implementation for assert macro | a | a | a |
| Character handling < ctype.h > | Shell | DXE | PEI |
| int isalnum(int) | C90, is implemented | a | a | a |
| int isalpha(int) | C90, is implemented | a | a | a |
| int iscntrl(int) | C90, is implemented | a | a | a |
| int isdigit(int) | C90, is implemented | a | a | a |
| int isgraph(int) | C90, is implemented | a | a | a |
| int islower(int) | C90, is implemented | a | a | a |
| int isprint(int) | C90, is implemented | a | a | a |
| int ispunct(int) | C90, is implemented | a | a | a |
| int isspace(int) | C90, is implemented | a | a | a |
| int isupper(int) | C90, is implemented | a | a | a |
| int isxdigit(int) | C90, is implemented | a | a | a |
| int tolower(int) | C90, is implemented | a | a | a |
| int toupper(int) | C90, is implemented | a | a | a |
| Errors < errno.h > | Shell | DXE | PEI |
| int *_errno(void) | C90, MSFT implementation for errno macro | a | | |
| Format conversion of integer types < inttypes.h > | Shell | DXE | PEI |
| intmax_t strtoimax(const char* strSource,char** endptr,int base) | C99, is implemented | a | a | a |
| uintmax_t strtoumax(const char* strSource, char** endptr, int base) | C99, is implemented | a | a | a |
| intmax_t wcstoimax(const wchar_t* strSource,wchar_t** endptr,int base) | C99, is implemented | a | a | a |
| uintmax_t wcstoumax(const wchar_t* strSource, wchar_t** endptr, int base) | C99, is implemented | a | a | a |
| Localization < locale.h > | Shell | DXE | PEI |
| struct lconv *localeconv(void) | C90, is implemented (C-locale) | a | a | a |
| char *setlocale(int category, const char *locale) | C90, is implemented (C-locale) | a | a | a |
| Nonlocal jumps < setjmp.h > | Shell | DXE | PEI |
| void longjmp(jmp_buf env, int val) | C90, is implemented | a | a | a |
| int setjmp(jmp_buf env) | C90, _setjmp is implemented | a | a | a |
| Signal handling < signal.h > | Shell | DXE | PEI |
| int raise(int sig) | C90, is implemented | a | | |
| void (*signal(int sig, void (*func)(int)))(int) | C90, is implemented | a | | |
| Input/output < stdio.h > | Shell | DXE | PEI |
| void clearerr(FILE *stream) | C90, is implemented | a | | |
| int fclose(FILE *stream) | C90, is implemented | a | | |
| int feof(FILE *stream) | C90, is implemented | a | | |
| int ferror(FILE *stream) | C90, is implemented | a | | |
| int fflush(FILE *stream) | C90, is implemented | a | | |
| int fgetc(FILE *stream) | C90, is implemented | a | | |
| int fgetpos(FILE * stream,fpos_t * pos) | C90, is implemented | a | | |
| char *fgets(char * s, int n,FILE * stream) | C90, is implemented | a | | |
| FILE *fopen(const char * filename,const char * mode) | C90, is implemented | a | | |
| int fprintf(FILE * stream,const char * format, ...) | C90, is implemented | a | | |
| int fputc(int c, FILE *stream) | C90, is implemented | a | | |
| int fputs(const char * s,FILE * stream) | C90, is implemented | a | | |
| size_t fread(void * ptr,size_t size, size_t nmemb,FILE * stream) | C90, is implemented | a | | |
| FILE *freopen(const char * filename,const char * mode,FILE * stream) | C90, is implemented | a | | |
| int fscanf(FILE * stream,const char * format, ...) | C90, is implemented | a | | |
| int fseek(FILE *stream, long int offset, int whence) | C90, is implemented | a | | |
| int fsetpos(FILE *stream, const fpos_t *pos) | C90, is implemented | a | | |
| long int ftell(FILE *stream) | C90, is implemented | a | | |
| size_t fwrite(const void * ptr,size_t size, size_t nmemb,FILE * stream) | C90, is implemented | a | | |
| int getc(FILE *stream) | C90, is implemented | a | | |
| int getchar(void) | C90, is implemented | a | | |
| char *gets(char *s) | C90, is implemented | a | | |
| void perror(const char *s) | C90, is implemented | a | | |
| int printf(const char * format, ...) | C90, is implemented | a | a | a |
| int putc(int c, FILE *stream) | C90, is implemented | a | | |
| int putchar(int c) | C90, is implemented | a | | |
| int puts(const char *s) | C90, is implemented | a | | |
| int remove(const char *filename) | C90, is implemented | a | | |
| int rename(const char *old, const char *new) | C90, is implemented | a | | |
| void rewind(FILE *stream) | C90, is implemented | a | | |
| int scanf(const char * format, ...) | C90, is implemented | a | | |
| void setbuf(FILE * stream,char * buf) | C90, is implemented | a | | |
| int setvbuf(FILE * stream,char * buf,int mode, size_t size) | C90, is implemented | a | | |
| int snprintf(char * s, size_t n,const char * format, ...) | C99, is implemented | a | a | a |
| int sprintf(char * s,const char * format, ...) | C90, is implemented | a | a | a |
| int sscanf(const char * s,const char * format, ...) | C90, is implemented | a | a | a |
| FILE *tmpfile(void) | C90, is implemented | a | | |
| char *tmpnam(char *s) | C90, is implemented | a | a | a |
| int ungetc(int c, FILE *stream) | C90, is implemented | a | | |
| int vfprintf(FILE * stream,const char * format, va_list arg) | C90, is implemented | a | | |
| int vfscanf(FILE * stream,const char * format, va_list arg) | C99, is implemented | a | | |
| int vprintf(const char * format, va_list arg) | C90, is implemented | a | a | a |
| int vscanf(const char * format, va_list arg) | C99, is implemented | a | | |
| int vsnprintf(char * s, size_t n,const char * format, va_list arg) | C99, is implemented | a | a | a |
| int _vsnwprintf(wchar_t* pszDest, size_t dwCount, const wchar_t* pszFormat, va_list ap) | MSFT specific, is implemented | a | a | a |
| int vsprintf(char * s,const char * format, va_list arg) | C90, is implemented | a | a | a |
| int vsscanf(const char * s,const char * format, va_list arg) | C99, is implemented | a | a | a |
| String handling < string.h > | Shell | DXE | PEI |
| char *_strdup(const char *strSource) | MSFT specific, is implemented | a | a | a |
| int _stricmp(const char *string1, const char *string2) | MSFT specific, is implemented | a | a | a |
| int _strnicmp(const char* pszDst, const char* pszSrc, size_t count) | MSFT specific, is implemented | a | a | a |
| void *memchr(const void *s, int c, size_t n) | C90, is implemented | a | a | a |
| int memcmp(const void *s1, const void *s2, size_t n) | C90, is implemented | a | a | a |
| void *memcpy(void * s1,const void * s2, size_t n) | C90, is implemented | a | a | a |
| void *memmove(void *s1, const void *s2, size_t n) | C90, is implemented | a | a | a |
| void *memset(void *s, int c, size_t n) | C90, is implemented | a | a | a |
| char *strcat(char * s1,const char * s2) | C90, is implemented | a | a | a |
| char *strchr(const char *s, int c) | C90, is implemented | a | a | a |
| int strcmp(const char *s1, const char *s2) | C90, is implemented | a | a | a |
| int strcoll(const char *s1, const char *s2) | C90, is implemented | a | a | a |
| char *strcpy(char * s1,const char * s2) | C90, is implemented | a | a | a |
| size_t strcspn(const char *s1, const char *s2) | C90, is implemented | a | a | a |
| char *strerror(int errnum) | C90, is implemented | a | a | a |
| size_t strlen(const char *s) | C90, is implemented | a | a | a |
| char *strncat(char * s1,const char * s2, size_t n) | C90, is implemented | a | a | a |
| int strncmp(const char *s1, const char *s2, size_t n) | C90, is implemented | a | a | a |
| char *strncpy(char * s1,const char * s2, size_t n) | C90, is implemented | a | a | a |
| char *strpbrk(const char *s1, const char *s2) | C90, is implemented | a | a | a |
| char *strchr(const char *s, int c) | C90, is implemented | a | a | a |
| size_t strspn(const char *s1, const char *s2) | C90, is implemented | a | a | a |
| char *strstr(const char *s1, const char *s2) | C90, is implemented | a | a | a |
| char *strtok(char * s1,const char * s2) | C90, is implemented | a | a | a |
| size_t strxfrm(char * s1,const char * s2, size_t n) | C90, is implemented | a | a | a |
| Date and time < time.h > | Shell | DXE | PEI |
| char *asctime(const struct tm *timeptr) | C90, is implemented | a | a | a |
| clock_t clock(void) | C90, is implemented | a | a | a |
| char *ctime(const time_t *timer) | C90, is implemented | a | a | a |
| double difftime(time_t time1, time_t time0) | C90, is implemented | a | a | a |
| struct tm *gmtime(const time_t *timer) | C90, is implemented | a | a | a |
| struct tm *localtime(const time_t *timer) | C90, is implemented | a | a | a |
| time_t mktime(struct tm *timeptr) | C90, is implemented | a | a | a |
| size_t strftime(char * s,size_t maxsize,const char * format,const struct tm * timeptr) | C90, is implemented | a | a | a |
| time_t time(time_t *timer) | C90, is implemented | a | a | a |
| Extended multibyte/wide character utilities < wchar.h > | Shell | DXE | PEI |
| wint_t btowc(int c) | C95, is implemented | a | a | a |
| double wcstod(const wchar_t * nptr,wchar_t ** endptr) | C95, is not yet implemented | | | |
| wint_t fgetwc(FILE *stream) | C95, is implemented | a | | |
| wchar_t *fgetws(wchar_t * s, int n,FILE * stream) | C95, is implemented | a | | |
| wint_t fputwc(wchar_t c, FILE *stream) | C95, is implemented | a | | |
| int fputws(const wchar_t * s,FILE * stream) | C95, is implemented | a | | |
| int fwide(FILE *stream, int mode) | C95, is implemented | a | | |
| int fwprintf(FILE * stream,const wchar_t * format, ...) | C95, is implemented | a | | |
| int fwscanf(FILE * stream,const wchar_t * format, ...) | C95, is implemented | a | | |
| wint_t getwc(FILE *stream) | C95, is implemented | a | | |
| wint_t getwchar(void) | C95, is implemented | a | | |
| size_t mbrlen(const char * s, size_t n,mbstate_t * ps) | C95, is not yet implemented | | | |
| size_t mbrtowc(wchar_t * pwc,const char * s, size_t n,mbstate_t * ps) | C95, is not yet implemented | | | |
| int mbsinit(const mbstate_t *ps) | C95, is not yet implemented | | | |
| size_t mbsrtowcs(wchar_t * dst,const char ** src, size_t len,mbstate_t * ps) | C95, is not yet implemented | | | |
| wint_t putwc(wchar_t c, FILE *stream) | C95, is implemented | a | | |
| wint_t putwchar(wchar_t c) | C95, is implemented | a | | |
| int swprintf(wchar_t * s, size_t n,const wchar_t * format, ...) | C95, is implemented | a | a | a |
| int swscanf(const wchar_t * s,const wchar_t * format, ...) | C95, is implemented | a | a | a |
| wint_t ungetwc(wint_t c, FILE *stream) | C95, is implemented | a | | |
| int vfwprintf(FILE * stream,const wchar_t * format, va_list arg) | C95, is implemented | a | | |
| int vfwscanf(FILE *stream, const wchar_t *format, va_list argptr) | C99, is implemented | a | | |
| int vswprintf(wchar_t * s, size_t n,const wchar_t * format, va_list arg) | C95, is implemented | a | a | a |
| int vswscanf(const wchar_t *buffer, const wchar_t *format, va_list arglist) | C99, is implemented | a | | |
| int vwprintf(const wchar_t * format,va_list arg) | C95, is implemented | | | |
| size_t wcrtomb(char * s, wchar_t wc,mbstate_t * ps) | C95, is not yet implemented | | | |
| wchar_t *wcscat(wchar_t * s1,const wchar_t * s2) | C95, is implemented | a | a | a |
| wchar_t *wcschr(const wchar_t *s, wchar_t c) | C95, is implemented | a | a | a |
| int wcscmp(const wchar_t *s1, const wchar_t *s2) | C95, is implemented | a | a | a |
| int wcscoll(const wchar_t *s1, const wchar_t *s2) | C95, is implemented | a | a | a |
| size_t wcscspn(const wchar_t *s1, const wchar_t *s2) | C95, is implemented | a | a | a |
| size_t wcsftime(wchar_t * s, size_t maxsize,const wchar_t * format,const struct tm * timeptr) | C95, is not yet implemented | | | |
| size_t wcslen(const wchar_t *s) | C95, is implemented | a | a | a |
| wchar_t *wcsncat(wchar_t * s1,const wchar_t * s2, size_t n) | C95, is implemented | a | a | a |
| int wcsncmp(const wchar_t *s1, const wchar_t *s2,size_t n) | C95, is implemented | a | a | a |
| wchar_t *wcsncpy(wchar_t * s1,const wchar_t * s2, size_t n) | C95, is implemented | a | a | a |
| int wcsnicmp(const wchar_t *s1, const wchar_t *s2,size_t n) | C95, is implemented | a | a | a |
| wchar_t *wcspbrk(const wchar_t *s1, const wchar_t *s2) | C95, is implemented | a | a | a |
| wchar_t *wcscpy(wchar_t * s1,const wchar_t * s2) | C95, is implemented | a | a | a |
| wchar_t *wcsrchr(const wchar_t *s, wchar_t c) | C95, is implemented | a | a | a |
| size_t wcsrtombs(char * dst,const wchar_t ** src, size_t len,mbstate_t * ps) | C95, is not yet implemented | | | |
| size_t wcsspn(const wchar_t *s1, const wchar_t *s2) | C95, is implemented | a | a | a |
| wchar_t *wcsstr(const wchar_t *s1, const wchar_t *s2) | C95, is implemented | a | a | a |
| wchar_t *wcstok(wchar_t * s1,const wchar_t * s2,wchar_t ** ptr) | C95, is implemented | a | a | a |
| long int wcstol(const wchar_t * nptr,wchar_t ** endptr, int base) | C95, is implemented | a | a | a |
| long long wcstoll(const wchar_t* strSource,wchar_t** endptr,int base) | C99, is implemented | a | a | a |
| unsigned long int wcstoul(const wchar_t * nptr,wchar_t ** endptr, int base) | C95, is implemented | a | a | a |
| unsigned long long wcstoull(const wchar_t* s, wchar_t** endptr, int base) | C99, is implemented | a | a | a |
| size_t wcsxfrm(wchar_t * s1,const wchar_t * s2, size_t n) | C95, is implemented | a | a | a |
| int wctob(wint_t c) | C95, is implemented | a | a | a |
| wchar_t *wmemchr(const wchar_t *s, wchar_t c, size_t n) | C95, is implemented | a | a | a |
| int wmemcmp(const wchar_t *s1, const wchar_t *s2,size_t n) | C95, is implemented | a | a | a |
| wchar_t *wmemcpy(wchar_t * s1,const wchar_t * s2, size_t n) | C95, is implemented | a | a | a |
| wchar_t *wmemmove(wchar_t *s1, const wchar_t *s2,size_t n) | C95, is implemented | a | a | a |
| wchar_t *wmemset(wchar_t *s, wchar_t c, size_t n) | C95, is implemented | a | a | a |
| int wprintf(const wchar_t * format, ...) | C95, is implemented | a | a | a |
| int wscanf(const wchar_t * format, ...) | C95, is not yet implemented | | | |
| General utilities < stdlib.h > | Shell | DXE | PEI |
| char* _i64toa(long long _Value, char* _Buffer, int _Radix) | MSFT specific, is implemented | a | a | a |
| wchar_t* _i64tow(long long _Value, wchar_t* _Buffer, int _Radix) | MSFT specific, is implemented | a | a | a |
| char* _itoa(int _Value, char* _Buffer, int _Radix) | MSFT specific, is implemented | a | a | a |
| wchar_t* _itow(int _Value, wchar_t* _Buffer, int _Radix) | MSFT specific, is implemented | a | a | a |
| char* _ltoa(long _Value, char* _Buffer, int _Radix) | MSFT specific, is implemented | a | a | a |
| wchar_t* _ltow(long _Value, wchar_t* _Buffer, int _Radix) | MSFT specific, is implemented | a | a | a |
| char* _ui64toa(unsigned long long _Value, char* _Buffer, int _Radix) | MSFT specific, is implemented | a | a | a |
| char* _ultoa(unsigned long _Value, char* _Buffer, int _Radix) | MSFT specific, is implemented | a | a | a |
| wchar_t* _ultow(unsigned long _Value, wchar_t* _Buffer, int _Radix) | MSFT specific, is implemented | a | a | a |
| void abort(void) | C90, is implemented | a | | |
| int abs(int j) | C90, is implemented | a | a | a |
| int atexit(void (*func)(void)) | C90, is implemented | a | a | a |
| double atof(const char *nptr) | C90, is not yet implemented | | | |
| int atoi(const char *nptr) | C90, is implemented | a | a | a |
| long int atol(const char *nptr) | C90, is implemented | a | a | a |
| void *bsearch(const void *key, const void *base,size_t nmemb, size_t size,int (*compar)(const void *, const void *)) | C90, is not yet implemented | | | |
| void *calloc(size_t nmemb, size_t size) | C90, is implemented | a | a | a |
| div_t div(int numer, int denom) | C90, is implemented | a | a | a |
| void exit(int status) | C90, is implemented | a | a | a |
| void free(void *ptr) | C90, is implemented | a | a | a |
| char *getenv(const char *name) | C90, is implemented | a | | |
| long int labs(long int j) | C90, is implemented | a | a | a |
| ldiv_t ldiv(long int numer, long int denom) | C90, is implemented | a | a | a |
| void *malloc(size_t size) | C90, is implemented | a | a | a |
| int mblen(const char *s, size_t n) | C90, is implemented | a | a | a |
| size_t mbstowcs(wchar_t * pwcs,const char * s, size_t n) | C90, is implemented | a | a | a |
| int mbtowc(wchar_t * pwc,const char * s, size_t n) | C90, is implemented | a | a | a |
| void qsort(void *base, size_t nmemb, size_t size,int (*compar)(const void *, const void *)) | C90, is implemented | a | a | a |
| int rand(void) | C90, is implemented | a | a | a |
| void *realloc(void *ptr, size_t size) | C90, is implemented | a | a | a |
| void srand(unsigned int seed) | C90, is implemented | a | a | a |
| double strtod(const char * nptr,char ** endptr) | C90, is not yet implemented | | | |
| long int strtol(const char * nptr,char ** endptr, int base) | C90, is implemented | a | a | a |
| unsigned long int strtoul(const char * nptr,char ** endptr, int base) | C90, is implemented | a | a | a |
| int system(const char *string) | C90, is implemented | a | | |
| size_t wcstombs(char * s,const wchar_t * pwcs, size_t n) | C90, is implemented | a | a | a |
| int wctomb(char *s, wchar_t wchar) | C90, is implemented | a | a | a |
| Wide character classification and mapping utilities < wctype.h > | Shell | DXE | PEI |
| int iswalnum(wint_t wc) | C95, is implemented | a | a | a |
| int iswalpha(wint_t wc) | C95, is implemented | a | a | a |
| int iswblank(wint_t wc) | C99, is implemented | a | a | a |
| int iswcntrl(wint_t wc) | C95, is implemented | a | a | a |
| int iswctype(wint_t wc, wctype_t desc) | C95, is implemented | a | a | a |
| int iswdigit(wint_t wc) | C95, is implemented | a | a | a |
| int iswgraph(wint_t wc) | C95, is implemented | a | a | a |
| int iswlower(wint_t wc) | C95, is implemented | a | a | a |
| int iswprint(wint_t wc) | C95, is implemented | a | a | a |
| int iswpunct(wint_t wc) | C95, is implemented | a | a | a |
| int iswspace(wint_t wc) | C95, is implemented | a | a | a |
| int iswupper(wint_t wc) | C95, is implemented | a | a | a |
| int iswxdigit(wint_t wc) | C95, is implemented | a | a | a |
| wint_t towctrans(wint_t wc, wctrans_t desc) | C95, is implemented | a | a | a |
| wint_t towlower(wint_t wc) | C95, is implemented | a | a | a |
| wint_t towupper(wint_t wc) | C95, is implemented | a | a | a |
| wctrans_t wctrans(const char *property) | C95, is implemented | a | a | a |
| wctype_t wctype(const char *property) | C95, is implemented | a | a | a |
| mathematical functions< math.h > |
| double acos(double x) | C90, is not yet implemented | | | |
| double asin(double x) | C90, is not yet implemented | | | |
| double atan(double x) | C90, is not yet implemented | | | |
| double atan2(double x, double y) | C90, is not yet implemented | | | |
| double ceil(double x) | C90, is not yet implemented | | | |
| double cos(double x) | C90, is not yet implemented | | | |
| double cosh(double x) | C90, is not yet implemented | | | |
| double exp(double x) | C90, is not yet implemented | | | |
| double fabs(double x) | C90, is not yet implemented | | | |
| double floor(double x) | C90, is not yet implemented | | | |
| double fmod(double x, double y) | C90, is not yet implemented | | | |
| double frexp(double value, int *exp) | C90, is not yet implemented | | | |
| double ldexp(double value, int exp) | C90, is not yet implemented | | | |
| double log(double value) | C90, is not yet implemented | | | |
| double log10(double value) | C90, is not yet implemented | | | |
| double modf(double value, double *iptr) | C90, is not yet implemented | | | |
| double pow(double x, double y) | C90, is not yet implemented | | | |
| double sin(double x) | C90, is not yet implemented | | | |
| double sinh(double x) | C90, is not yet implemented | | | |
| double sqrt(double x) | C90, is not yet implemented | | | |
| double tan(double x) | C90, is not yet implemented | | | |
| double tan(double x) | C90, is not yet implemented | | | |
| non-C-Standard and Microsoft specific functions< io.h > | Shell | DXE | PEI |
| int _isatty( int fd ); | MSFT specific, is implemented | a | | |
| intptr_t _findfirst(const char *filespec, struct _finddata_t *fileinfo) | MSFT specific, is implemented | a | | |
| int _findnext(intptr_t handle,struct _finddata_t *fileinfo) | MSFT specific, is implemented | a | | |
| int _findclose(intptr_t handle) | MSFT specific, is implemented | a | | |
| non-C-Standard and Microsoft specific functions< direct.h > | Shell | DXE | PEI |
| int _mkdir(const char *dirname) | MSFT specific, is implemented | a | | |
| non-C-Standard and Microsoft specific / POSIX functions< sys/stat.h > | Shell | DXE | PEI |
| int _stat64i32(const char *path, struct _stat64i32 *buffer) | MSFT specific, is implemented | a | | |