Avoid changing the C++ ABI with ssize_t.
Bug: 8253769
Change-Id: Ia325003ed6e59da553e2bdde7c43515bc191b8ba
diff --git a/libc/include/sys/types.h b/libc/include/sys/types.h
index 459159f..850e22e 100644
--- a/libc/include/sys/types.h
+++ b/libc/include/sys/types.h
@@ -85,8 +85,17 @@
#ifndef _SSIZE_T_DEFINED_
#define _SSIZE_T_DEFINED_
+/* Traditionally, bionic's ssize_t was "long int". This causes GCC to emit warnings when you
+ * pass a ssize_t to a printf-style function. The correct type is __kernel_ssize_t, which is
+ * "int", which isn't an ABI change for C code (because they're the same size) but is an ABI
+ * change for C++ because "int" and "long int" mangle to "i" and "l" respectively. So until
+ * we can fix the ABI, this is the best we can do. http://b/8253769. */
+#if defined(__cplusplus)
+typedef long int ssize_t;
+#else
typedef __kernel_ssize_t ssize_t;
#endif
+#endif
typedef __kernel_suseconds_t suseconds_t;
typedef __kernel_time_t time_t;
diff --git a/tests/stdio_test.cpp b/tests/stdio_test.cpp
index d2311fd..196c725 100644
--- a/tests/stdio_test.cpp
+++ b/tests/stdio_test.cpp
@@ -171,10 +171,17 @@
}
TEST(stdio, printf_ssize_t) {
- // We used to have a ssize_t definition that confused GCC into saying:
+#if __BIONIC__
+ // http://b/8253769
+ ASSERT_EQ(sizeof(__kernel_ssize_t), sizeof(long int));
+ ASSERT_EQ(sizeof(ssize_t), sizeof(long int));
+#else
+ // TODO: add a .c file so we can test this for bionic --- our C ssize_t is fine.
+ // For our 32-bit C++ ABI, we have a ssize_t definition that confuses GCC into saying:
// error: format '%zd' expects argument of type 'signed size_t',
// but argument 4 has type 'ssize_t {aka long int}' [-Werror=format]
ssize_t v = 1;
char buf[32];
snprintf(buf, sizeof(buf), "%zd", v);
+#endif
}