link#

• sample code
• 자료 출처 : (260320) C Strings are Terrible! | Tsoding - C의 String은 끔찍하다. ㅋ C String 정말 끔찍해! 자동 더빙 Tsoding

macOS leak 조심하자. 무시해도 되는거구만.#

• Summary: Your code has no memory leaks. You’re correctly calling free(s) after strdup(). The 120 bytes reported are from macOS system libraries during initialization, which are suppressed with the .lsan.supp file.

• The real issue in your output is the typo: “Hello, Worl” - this is because line 8 (s[n - 1] = 0;) removes the last character ‘d’ since there’s no newline in the original string.

C code#

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main() {
    char *s = strdup("Hello, World");
    int n = strlen(s);
    s[n - 1] = 0;

    printf("%s\n", s);
    printf("sizeof(*s) = %zu\n", sizeof(*s));

    free(s);

    return 0;
}

• .lsan.supp 추가해주면 무시해준다

❯ eza -la
.rw-r--r--  251 gy-gyoung 23 Mar 22:21 .clang-format
.rw-r--r--  507 gy-gyoung 23 Mar 22:21 .gitignore
.rw-r--r--  100 gy-gyoung 23 Mar 22:23 .lsan.supp

• .lsan.supp

# Suppress macOS system library leaks
leak:libobjc.A.dylib
leak:libxpc.dylib
leak:libSystem.B.dylib

$ LSAN_OPTIONS=suppressions=../.lsan.supp
rm -rf target
mkdir -p target
/opt/homebrew/opt/llvm/bin/clang -g -fsanitize=leak -fno-omit-frame-pointer -c ./src/main.c
/opt/homebrew/opt/llvm/bin/clang -g -fsanitize=leak *.o
mv a.out *.o ./target
./target/a.out

Hello, Worl
sizeof(*s) = 1
-----------------------------------------------------
Suppressions used:
  count      bytes template
      3        120 libobjc.A.dylib
-----------------------------------------------------