Define an __errno_location function. (#347)

This function returns the address of `errno`, which makes it easier to access from non-C languages since `errno` is a thread-local variable which requires a special ABI.
WebAssembly · Nov 28, 2022 · 2bb5abe · 2bb5abe
1 parent a00bf32
commit 2bb5abe
Show file tree

Hide file tree

Showing 3 changed files with 7 additions and 0 deletions.
diff --git a/expected/wasm32-wasi/posix/defined-symbols.txt b/expected/wasm32-wasi/posix/defined-symbols.txt
@@ -48,6 +48,7 @@ __do_des
 __do_orphaned_stdio_locks
 __duplocale
 __env_rm_add
+__errno_location
 __exp2f_data
 __exp_data
 __expo2

diff --git a/expected/wasm32-wasi/single/defined-symbols.txt b/expected/wasm32-wasi/single/defined-symbols.txt
@@ -38,6 +38,7 @@ __des_setkey
 __do_des
 __duplocale
 __env_rm_add
+__errno_location
 __exp2f_data
 __exp_data
 __expo2

diff --git a/libc-bottom-half/sources/__errno_location.c b/libc-bottom-half/sources/__errno_location.c
@@ -0,0 +1,5 @@
+#include <errno.h>
+
+int *__errno_location(void) {
+    return &errno;
+}