# \[PATCH v2 05/10\] grep/pcre2: add GREP\_PCRE2\_DEBUG\_MALLOC debug mode

- From: Ævar Arnfjörð Bjarmason \<hidden\>
- Date: 2021-02-18 00:09:00 
- List: git
- Page: https://ratatoskr.run/git/2021/02/7876817
- Thread: https://ratatoskr.run/git/2019/10/7825431/t.md

```text
Add optional printing of PCREv2 allocations to stderr for a developer
who manually changes the GREP_PCRE2_DEBUG_MALLOC definition to "1".

You need to manually change the definition in the source file similar
to the DEBUG_MAILMAP, there's no Makefile knob for this.

This will be referenced a subsequent commit, and is generally useful
to manually see what's going on with PCREv2 allocations while working
on that code.

Signed-off-by: Ævar Arnfjörð Bjarmason <redacted>
---
 grep.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/grep.c b/grep.c
index f96d86c9293..7d262a23d88 100644
--- a/grep.c
+++ b/grep.c
@@ -42,15 +42,25 @@ static struct grep_opt grep_defaults = {
 
 #ifdef USE_LIBPCRE2
 static pcre2_general_context *pcre2_global_context;
+#define GREP_PCRE2_DEBUG_MALLOC 0
 
 static void *pcre2_malloc(PCRE2_SIZE size, MAYBE_UNUSED void *memory_data)
 {
 	void *pointer = malloc(size);
+#if GREP_PCRE2_DEBUG_MALLOC
+	static int count = 1;
+	fprintf(stderr, "PCRE2:%p -> #%02d: alloc(%lu)\n", pointer, count++, size);
+#endif
 	return pointer;
 }
 
 static void pcre2_free(void *pointer, MAYBE_UNUSED void *memory_data)
 {
+#if GREP_PCRE2_DEBUG_MALLOC
+	static int count = 1;
+	if (pointer)
+		fprintf(stderr, "PCRE2:%p -> #%02d: free()\n", pointer, count++);
+#endif
 	free(pointer);
 }
 #endif
-- 
2.30.0.284.gd98b1dd5eaa7

```