ltrace(1)
ltrace [opts] [prg]
-f .......... follow child processes on fork(2)
-p <pid> .... attach to running process
-o <file> ... log output into <file>
-l <filter> . show who calls into lib matched by <filter>
-C .......... demangle
Example
List which program/libs call into libstdc++
:
ltrace -l '*libstdc++*' -C -o ltrace.log ./main