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Asked: 2026-05-25T13:48:38+00:00

I have a curious memory leak, it seems that the library function to_unbounded_string is

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I have a curious memory leak, it seems that the library function to_unbounded_string is leaking!

Code snippets: 

procedure Parse (Str    : in     String;

… do stuff… 

declare
   New_Element : constant Ada.Strings.Unbounded.Unbounded_String :=
     Ada.Strings.Unbounded.To_Unbounded_String (Str); -- this leaks
begin

valgrind output: 

==6009== 10,276 bytes in 1 blocks are possibly lost in loss record 153 of 153
==6009==    at 0x4025BD3: malloc (vg_replace_malloc.c:236)
==6009==    by 0x42703B8: __gnat_malloc (in /usr/lib/libgnat-4.4.so.1)
==6009==    by 0x4269480: system__secondary_stack__ss_allocate (in /usr/lib/libgnat-4.4.so.1)
==6009==    by 0x414929B: ada__strings__unbounded__to_unbounded_string (in /usr/lib/libgnat-4.4.so.1)
==6009==    by 0x80F8AD4: syntax__parser__dash_parser__parseXn (token_parser_g.adb:35)

Where token_parser_g.adb:35 is listed above as the “– this leaks” line.

Other info: Gnatmake version 4.4.5. gcc version 4.4 valgrind version valgrind-3.6.0.SVN-Debian, valgrind options -v –leak-check=full –read-var-info=yes –show-reachable=no

Any help or insights appreciated,

NWS.

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1 Answer

  1. Editorial Team

    Valgrind clearly says that there is possibly a memory leak. It doesn’t necessarily mean there is one. For example, if first call to that function allocates a pool of memory that is re-used during the life time of the program but is never freed, Valgrind will report it as a possible memory leak, even though it is not, as this is a common practice and memory will be returned to OS upon process termination.

    Now, if you think that there is a memory leak for real, call this function in a loop, and see it memory continues to grow. If it does – file a bug report or even better, try to find and fix the leak and send a patch along with a bug report.

    Hope it helps.

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