wcstoimax / wcstoumax (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 <stddef.h>
#include <inttypes.h>

intmax_t  wcstoimax(const wchar_t *restrict nptr,
                    wchar_t **restrict endptr, int base);
uintmax_t wcstoumax(const wchar_t *restrict nptr,
                    wchar_t **restrict endptr, int base);

Declared in /usr/include/inttypes.h lines 366-374 (parameterized on __gwchar_t, which is wchar_t in C). Under #if __GLIBC_USE (C23_STRTOL) (line 377) calls redirect to __isoc23_wcstoimax/__isoc23_wcstoumax, which additionally accept 0b/0B prefixes in base 0 or 2 (header comment lines 374-376). inttypes.h pulls in stddef.h with __need_wchar_t when wchar_t is not already defined (lines 36-38).

Semantics

Just like wcstol/wcstoul except that they return intmax_t and uintmax_t respectively (wcstoimax(3) DESCRIPTION; manual, arith.texi lines 2846-2871). Base handling, whitespace, sign, tail pointer and the C23 binary-prefix extension are those of wcstol family; overflow returns INTMAX_MAX, INTMAX_MIN or UINTMAX_MAX with errno = ERANGE, and no conversion returns 0 with *endptr = nptr (as for strtoimax(3) RETURN VALUE). Both were introduced in ISO C99 (arith.texi lines 2852, 2871).

Gotchas and portability

• The header declares them with __gwchar_t; this is a build-time alias for wchar_t, so the man page and manual both present plain wchar_t prototypes.
• Weak-alias structure on this LP64 host: wcstoimax shares one address with wcstol and wcstoumax with wcstoul, matching intmax_t = long.
• musl 1.2.5: both declared (musl include/inttypes.h lines 22-23), making this one of the few intmax pieces portable across musl and glibc unchanged.
• See the narrow twins on the strtoimax page.

References

• glibc manual: arith.texi, node Parsing of Integers (lines 2846-2871)
• man3: wcstoimax(3) (covers wcstoumax)
• headers: /usr/include/inttypes.h
• symbols: nm -D --with-symbol-versions libc.so.6