### C Library Functions: Type Conversion

Function | Header File | Description
atof | stdlib.h | Converts a character string to a floating-point value.
atoi | stdlib.h | Converts a character string to an integer.
atol | stdlib.h | Converts a character string to a long integer.
_atold | stdlib.h math.h | Converts a character string to a long double value.
atoll | stdlib.h | Converts a character string to a long long integer.
ecvt | stdlib.h | Converts a floating-point number to a character string.
fcvt | stdlib.h | Converts a floating-point number to a character string, rounding according to the FORTRAN F format.
gcvt | stdlib.h | Converts a floating-point value to a character string, rounding according to the FORTRAN F or FORTRAN E formats.
_itoa | stdlib.h | Converts the digits of an integer to a character string.
_ltoa | stdlib.h | Converts the digits of a long integer to a character string.
strtod | stdlib.h | Converts a character string to a double value.
strtol | stdlib.h | Converts a character string to a long integer.
strtold | stdlib.h | Converts a character string to a long double value.
strtoll | stdlib.h | Converts a character string to a long long integer.
strtoul | stdlib.h | Converts a string to an unsigned long integer.
strtoull | stdlib.h | Converts a string to an unsigned long long integer.
_ultoa | stdlib.h | Converts the values of an unasigned long value to a character string.
_ulltoa | stdlib.h | Converts the values of an unasigned long long value to a character string.
wcstod | wchar.h | Converts a wide character string to a double value.
wcstol | wchar.h | Converts a wide character string to a long integer.
wcstoul | wchar.h | Converts a wide character string to an unsigned long integer.
wctob | wchar.h | Converts a wide character to a single-byte character.

Multibyte and Wide-Character Type Conversion

Function | Header File | Description
btowc | stdio.h wchar.h |
mbrtowc | wchar.h | Converts a multibyte character to a wide character (wchar_t); restartable version of mbtowc.
mbsrtowcs | wchar.h | Converts a multibyte character string to a wide character (wchar_t) string; restartable version of mbstowcs.
mbstowcs | stdlib.h | Converts a multibyte character string to a wide character (wchar_t) string.
mbtowc | stdlib.h | Converts a multibyte character to a wide character (wchar_t).
wcrtomb | wchar.h | Converts a wide character (wchar_t) to a multibyte character; restartable version of wctomb.
wcsrtombs | wchar.h | Converts a wide character (wchar_t) string to a multibyte character string; restartable version of wctomb.
wcstombs | stdlib.h | Converts a wide character (wchar_t) string to a multibyte character string.
wctomb | stdlib.h | Converts a wide character (wchar_t) to a multibyte character.

Alphabetical Listing of IBM C and C++ Compilers Functions and Macros