Valgrind does not show which line the error occurred

Question

I’m trying to use Valgrind for Linux in order to check for memory loss, however the error shown in the terminal does not show on which specific line it is.

==4873== Address 0x4a4e047 is 0 bytes after a block of size 7 alloc’d

==4873== at 0x483DD99: calloc (in /usr/lib/x86_64-linux-gnu/Valgrind/vgpreload_memcheck-amd64-linux.so)

==4873== by 0x109221: getName (in /home/Rodrigo/Documents/Vscodetest/a. out)

==4873== by 0x1091D5: main (in /home/Rodrigo/Documents/Vscodetest/a. out)

Answer 1

To make the valgrind display the lines, you can first compile the program using the GCC with the flag -g which indicates for the compilation to be performed by providing debug information:

gcc -g meu_programa.c -o meu_programa

When you run Valgrind, enter the flag --leak-check with the value full:

valgrind --leak-check=full ./meu_programa

Valgrind should display more details about the memory leak identified. As an example, for a program where I have not released the memory of a char* that had been allocated earlier, the message below was displayed on my terminal:

==387== 20 bytes in 1 blocks are definitely lost in loss record 1 of 1
==387==    at 0x483B7F3: malloc (in /usr/lib/x86_64-linux-gnu/valgrind/vgpreload_memcheck-amd64-linux.so)
==387==    by 0x1091CD: main (practice.c:8)

I hope I’ve helped in some way.