Changeset 183788f1 in mainline for uspace/libc/generic/io/vprintf.c

Timestamp:

2007-04-09T16:17:25Z (18 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

36f19c0

Parents:

de33dab

Message:

Remove printf() serialization from thread1 test in tester.
The agreement among developers seems to be that:

• there _must_ be a futex to serialize access to printf()
• there _must_ be pseudo thread serialization in printf()
• the best place for this is vprintf(), the one that goes to console

File:

• uspace/libc/generic/io/vprintf.c (modified) (2 diffs)

uspace/libc/generic/io/vprintf.c

@@ -37 +37 @@
 #include <unistd.h>
 #include <io/printf_core.h>
+#include <futex.h>
+#include <async.h>
+
+static atomic_t printf_futex = FUTEX_INITIALIZER;
 
 static int vprintf_write(const char *str, size_t count, void *unused)
@@ -50 +54 @@
 int vprintf(const char *fmt, va_list ap)
 {
-        struct printf_spec ps = {(int(*)(void *, size_t, void *)) vprintf_write, NULL};
-        
+        struct printf_spec ps = {
+                (int (*)(void *, size_t, void *)) vprintf_write,
+                 NULL
+        };
+        /*
+         * Prevent other threads to execute printf_core()
+         */
+        futex_down(&printf_futex);
+        /*
+         * Prevent other pseudo threads of the same thread
+         * to execute printf_core()
+         */
+        async_serialize_start();
         int ret = printf_core(fmt, &ps, ap);
-        
+        async_serialize_end();
+        futex_up(&printf_futex);
         return ret;
 }