rts: Always truncate output fileswip/T16993

Previously there were numerous places in the RTS where we would fopen
with the "w" flag string. This is wrong as it will not truncate the
file. Consequently if we write less data than the previous length of the
file we will leave garbage at its end.

Fixes #16993.

1 files changed, 1 insertions, 1 deletions

diff --git a/rts/Hpc.c b/rts/Hpc.c
index 9ba9b04b61..abf85430ac 100644
--- a/rts/Hpc.c
+++ b/rts/Hpc.c
@@ -388,7 +388,7 @@ exitHpc(void) {
   // not clober the .tix file.
 
   if (hpc_pid == getpid()) {
-    FILE *f = __rts_fopen(tixFilename,"w");
+    FILE *f = __rts_fopen(tixFilename,"w+");
     writeTix(f);
   }