wcstol / wcstoll / wcstoq / wcstoul / wcstoull / wcstouq (3) - glibc

Split from the chapter glibc: arithmetic functions into the per-function layout; see the method page and the glibc ledger for coverage status.

Declaration and gates

#include <wchar.h>

long          wcstol (const wchar_t *restrict nptr,
                      wchar_t **restrict endptr, int base);
unsigned long wcstoul(const wchar_t *restrict nptr,
                      wchar_t **restrict endptr, int base);
long long          wcstoll (const wchar_t *restrict nptr,    /* __USE_ISOC99 */
                            wchar_t **restrict endptr, int base);
unsigned long long wcstoull(const wchar_t *restrict nptr,    /* __USE_ISOC99 */
                            wchar_t **restrict endptr, int base);
long long          wcstoq (const wchar_t *restrict nptr,     /* __USE_GNU */
                           wchar_t **restrict endptr, int base);
unsigned long long wcstouq(const wchar_t *restrict nptr,     /* __USE_GNU */
                           wchar_t **restrict endptr, int base);

Declarations in /usr/include/wchar.h: wcstol line 455, wcstoul 460, wcstoll/wcstoull under #ifdef __USE_ISOC99 (lines 464-479), wcstoq/wcstouq under #ifdef __USE_GNU (lines 480-494). Under #if __GLIBC_USE (C23_STRTOL) (line 497) calls redirect to __isoc23_wcstol etc., which accept 0b/0B prefixes in base 0 or 2.

Semantics

wcstol is equivalent to strtol in nearly all aspects but handles wide character strings; likewise wcstoul for strtoul (manual, arith.texi lines 2721-2727, 2748-2754), wcstoll/wcstoull for strtoll/strtoull (arith.texi lines 2773-2812). Parsing: leading wide space, optional sign, digits in base (0 auto-detects, otherwise 2-36; invalid base gives 0l and errno = EINVAL), tail pointer stored via endptr; overflow returns LONG_MAX/LONG_MIN (or the ULONG_MAX/LLONG_MAX/ULLONG_MAX twins) with errno = ERANGE (arith.texi lines 2670-2718). wcstoq is equivalent to strtoq and wcstouq to strtouq, both GNU extensions (arith.texi lines 2788-2794, 2821-2827).

Gotchas and portability

• On this LP64 host nm shows the pairs collapse: wcstol, wcstoll and wcstoq share one address, as do wcstoul, wcstoull and wcstouq – the quad names are pure aliases.
• wcstoq/wcstouq need _GNU_SOURCE; the ISO names need no macro except the C99 pair.
• musl 1.2.5: wcstol, wcstoul, wcstoll, wcstoull declared (musl include/wchar.h lines 100-104); wcstoq/wcstouq absent.
• See also strtoimax page for the narrow strtoq/strtouq twins and wcstoimax page for the intmax forms.

References

• glibc manual: arith.texi, node Parsing of Integers (lines 2635-2943)
• headers: /usr/include/wchar.h
• man3: strtol(3) (NOTES cover strtoq), strtoul(3) (covers strtouq), wcstoimax(3) for the intmax wide pair
• symbols: nm -D --with-symbol-versions libc.so.6