common, vo_opengl: add/use helper for formatted strings on the stack

Seems like I really like this C99 idiom. No reason not to generalize it
do snprintf(). Introduce mp_tprintf(), which basically this idiom to
snprintf(). This macro looks like it returns a string that was allocated
with alloca() on the caller site, except it's portable C99/C11. (And
unlike alloca(), the result is valid only within block scope.)

Use it in 2 places in the vo_opengl code. But it has the potential to
make a whole bunch of weird looking code look slightly nicer.

1 files changed, 9 insertions, 0 deletions

diff --git a/common/common.c b/common/common.c
index eead096d5a..a07af8c461 100644
--- a/common/common.c
+++ b/common/common.c
@@ -287,3 +287,12 @@ char *mp_tag_str_buf(char *buf, size_t buf_size, uint32_t tag)
     }
     return buf;
 }
+
+char *mp_tprintf_buf(char *buf, size_t buf_size, const char *format, ...)
+{
+    va_list ap;
+    va_start(ap, format);
+    vsnprintf(buf, buf_size, format, ap);
+    va_end(ap);
+    return buf;
+}