gdb doesn't stop on breakpoint

Question

I'm trying to debug a shared library which run under check in unit-testing scenario. The shared library is statically linked (no `dlload`) and both the unit-testing application and the shared library are compiled with debugging symbols (`-g`) In `gdb` I want to set a breakpoint in a function contained in the shared library. I set a breakpoint successfully, but when it runs it just passes over the break-point. What I've tried already: I placed a `printf` in the shared library, it is printed out, so the function is actually called. Here's the Makefile I'm using for compilation: ``` SHELL = /bin/sh CC = gcc CFLAGS = -g -Wall -std=gnu99 -Iinclude EXTRA_FLAGS = -fPIC -shared LIBFLAGS = -fPIC -shared LDFLAGS = -shared -pthread -lcheck DEBUGFLAGS = -O0 -D _DEBUG RELEASEFLAGS = -O2 -D NDEBUG -combine -fwhole-program TEST_LDFLAGS = -lcheck -lllist -Llib -Wl,-rpath $(OBJDIR) OBJDIR = lib TARGET = $(OBJDIR)/libllist.so TEST_TARGET = starttest SOURCES = $(shell echo src/*.c) HEADERS = $(shell ech…

Accepted Answer

I don't know specifics of the `check` framework you are using, but some such frameworks execute code-under-test in a child process. If `check` does that, then your behavior is expected -- you are only debugging the parent process, but your code executes in a child.

You can easily confirm this guess: replace the `printf` in your code with `abort`. If GDB doesn't stop on `SIGABRT`, then my guess is likely correct, and you'll want to `(gdb) set follow-fork-mode child`.

Alternatively, read up on multi-inferior debugging. You can ask GDB to debug both the parent and the child with `set detach-on-fork off` (documentation).

gdb doesn't stop on breakpoint

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