Floating Functions

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This topic describes how to write portable code that correctly uses the floating definitions of RTL functions. The list of floating functions is useful for choosing the correct variant of a function, in particular in regards to using the default string type, UnicodeString.

Example of Writing Portable Code Using _TCHAR

RTL functions are available in either ANSI/MBCS or Unicode definitions. For example, the RTL function strlen can be used in ANSI/MBCS mode as follows:

void StorePersonData(const char* name)
{
   PersistToDB(name, strlen(name));
}

A more portable way of writing this code is:

void StorePersonData(const _TCHAR* name)
{
   PersistToDB(name, _tcstrlen(name));
}

This example assumes that PersistToDB has a Unicode version. Note that for functions that are not going to change or float, you should use either char or wchar_t.

List of Floating Definitions from tchar.h

The following table is derived from the tchar.h header file:

• The char/ANSI column lists the ANSI version of the floating functions that are appropriate when _TCHAR is mapped to char.
• The wchar_t/UNICODE column lists the UNICODE version of the floating functions that are appropriate when _TCHAR is mapped to wchar_t.
• The _TCHAR/Portable column lists the portable version of the floating functions, which maps to the appropriate function (either the ANSI or UNICODE version) as determined by the current setting of the _TCHAR maps to mapping option.

The recommended functions to use in C++Builder are those listed in the _TCHAR/Portable column, coupled with the use of _TCHAR (rather than char or wchar_t) in your code.

Floating Function Definitions from tchar.h:

char / ANSI	wchar_t / UNICODE	_TCHAR / Portable
_access	_waccess	_taccess
_atoi64	_wtoi64	_tstoi64
_atoi64	_wtoi64	_ttoi64
_cgets	_cgetws	cgetts
_chdir	_wchdir	_tchdir
_chmod	_wchmod	_tchmod
_cprintf	_cwprintf	_tcprintf
_cputs	_cputws	_cputts
_creat	_wcreat	_tcreat
_cscanf	_cwscanf	_tcscanf
_ctime64	_wctime64	_tctime64
_execl	_wexecl	_texecl
_execle	_wexecle	_texecle
_execlp	_wexeclp	_texeclp
_execlpe	_wexeclpe	_texeclpe
_execv	_wexecv	_texecv
_execve	_wexecve	_texecve
_execvp	_wexecvp	_texecvp
_execvpe	_wexecvpe	_texecvpe
_fdopen	_wfdopen	_tfdopen
_fgetchar	_fgetwchar	_fgettchar
_findfirst	_wfindfirst	_tfindfirst
_findnext64	_wfindnext64	_tfindnext64
_findnext	_wfindnext	_tfindnext
_findnexti64	_wfindnexti64	_tfindnexti64
_fputchar	_fputwchar	_fputtchar
_fsopen	_wfsopen	_tfsopen
_fullpath	_wfullpath	_tfullpath
_getch	_getwch	_gettch
_getche	_getwche	_gettche
_getcwd	_wgetcwd	_tgetcwd
_getdcwd	_wgetdcwd	_tgetdcwd
_ltoa	_ltow	_ltot
_makepath	_wmakepath	_tmakepath
_mkdir	_wmkdir	_tmkdir
_mktemp	_wmktemp	_tmktemp
_open	_wopen	_topen
_popen	_wpopen	_tpopen
_putch	_putwch	_puttch
_putenv	_wputenv	_tputenv
_rmdir	_wrmdir	_trmdir
_scprintf	_scwprintf	_sctprintf
_searchenv	_wsearchenv	_tsearchenv
_snprintf	_snwprintf	_sntprintf
_snscanf	_snwscanf	_sntscanf
_sopen	_wsopen	_tsopen
_spawnl	_wspawnl	_tspawnl
_spawnle	_wspawnle	_tspawnle
_spawnlp	_wspawnlp	_tspawnlp
_spawnlpe	_wspawnlpe	_tspawnlpe
_spawnv	_wspawnv	_tspawnv
_spawnve	_wspawnve	_tspawnve
_spawnvp	_wspawnvp	_tspawnvp
_spawnvpe	_wspawnvpe	_tspawnvpe
_splitpath	_wsplitpath	_tsplitpath
_stat64	_wstat64	_tstat64
_stat	_wstat	_tstat
_stati64	_wstati64	_tstati64
_strdate	_wstrdate	_tstrdate
_strdec	_wcsdec	_tcsdec
_strdup	_wcsdup	_tcsdup
_stricmp	_wcsicmp	_tcsicmp
_stricoll	_wcsicoll	_tcsicoll
_strinc	_wcsinc	_tcsinc
_strlwr	_wcslwr	_tcslwr
_strncnt	_wcsncnt	_tcsnbcnt
_strncnt	_wcsncnt	_tcsnccnt
_strncnt	_wcsncnt	_tcsnccnt
_strncoll	_wcsncoll	_tcsnccoll
_strnextc	_wcsnextc	_tcsnextc
_strnicmp	_wcsnicmp	_tcsncicmp
_strnicmp	_wcsnicmp	_tcsnicmp
_strnicoll	_wcsnicoll	_tcsncicoll
_strnicoll	_wcsnicoll	_tcsnicoll
_strninc	_wcsninc	_tcsninc
_strnset	_wcsnset	_tcsncset
_strnset	_wcsnset	_tcsnset
_strrev	_wcsrev	_tcsrev
_strset	_wcsset	_tcsset
_strspnp	_wcsspnp	_tcsspnp
_strtime	_wstrtime	_tstrtime
_strtoi64	_wcstoi64	_tcstoi64
_strtoui64	_wcstoui64	_tcstoui64
_strupr	_wcsupr	_tcsupr
_tempnam	_wtempnam	_ttempnam
_ui64toa	_ui64tow	_ui64tot
_ultoa	_ultow	_ultot
_ungetch	_ungetwch	_ungettch
_unlink	_wunlink	_tunlink
_utime64	_wutime64	_tutime64
_utime	_wutime	_tutime
_vscprintf	_vscwprintf	_vsctprintf
_vsnprintf	_vsnwprintf	_vsntprintf
asctime	_wasctime	_tasctime
atof	_wtof	_tstof
atoi	_wtoi	_tstoi
atoi	_wtoi	_ttoi
atol	_wtol	_tstol
atol	_wtol	_ttol
ctime	_wctime	_tctime
fgetc	fgetwc	_fgettc
fgets	fgetws	_fgetts
fopen	_wfopen	_tfopen
fprintf	fwprintf	_ftprintf
fputc	fputwc	_fputtc
fputs	fputws	_fputts
freopen	_wfreopen	_tfreopen
fscanf	fwscanf	_ftscanf
getc	getwc	_gettc
getchar	getwchar	_gettchar
getenv	_wgetenv	_tgetenv
gets	getws	_getts
isalnum	iswalnum	_istalnum
isalpha	iswalpha	_istalpha
isascii	iswascii	_istascii
iscntrl	iswcntrl	_istcntrl
isdigit	iswdigit	_istdigit
isgraph	iswgraph	_istgraph
islower	iswlower	_istlower
isprint	iswprint	_istprint
ispunct	iswpunct	_istpunct
isspace	iswspace	_istspace
isupper	iswupper	_istupper
isxdigit	iswxdigit	_istxdigit
main	wmain	_tmain
perror	_wperror	_tperror
printf	wprintf	_tprintf
putc	putwc	_puttc
putchar	putwchar	_puttchar
puts	_putws	_putts
remove	_wremove	_tremove
rename	_wrename	_trename
scanf	wscanf	_tscanf
setlocale	_wsetlocale	_tsetlocale
sprintf	swprintf	_stprintf
sscanf	swscanf	_stscanf
strcat	wcscat	_tcscat
strchr	wcschr	_tcschr
strcmp	wcscmp	_tcscmp
strcoll	wcscoll	_tcscoll
strcpy	wcscpy	_tcscpy
strcspn	wcscspn	_tcscspn
strerror	_wcserror	_tcserror
strftime	wcsftime	_tcsftime
strlen	wcslen	_tcsclen
strlen	wcslen	_tcslen
strncat	wcsncat	_tcsncat
strncat	wcsncat	_tcsnccat
strncmp	wcsncmp	_tcsnccmp
strncmp	wcsncmp	_tcsncmp
strncpy	wcsncpy	_tcsnccpy
strncpy	wcsncpy	_tcsncpy
strpbrk	wcspbrk	_tcspbrk
strrchr	wcsrchr	_tcsrchr
strspn	wcsspn	_tcsspn
strstr	wcsstr	_tcsstr
strtod	wcstod	_tcstod
strtok	wcstok	_tcstok
strtol	wcstol	_tcstol
strtoul	wcstoul	_tcstoul
strxfrm	wcsxfrm	_tcsxfrm
system	_wsystem	_tsystem
tmpnam	_wtmpnam	_ttmpnam
tolower	towlower	_totlower
toupper	towupper	_totupper
ungetc	ungetwc	_ungettc
vfprintf	vfwprintf	_vftprintf
vprintf	vwprintf	_vtprintf
vsprintf	vswprintf	_vstprintf
WinMain	wWinMain	_tWinMain

See Also

• TCHAR Mapping
• Unicode in RAD Studio
• Enabling Applications for Unicode
• Enabling C++ Applications for Unicode
• Cheat Sheet: Unicode-enabling Microsoft C/C++ Source Code
• C Run-Time Library Reference