Setting a Breakpoint in a Shared Library

dbx provides full debugging support for code that uses the programmatic interface to the run-time linker: code that calls dlopen(), dlclose() and their associated functions. The run-time linker binds and unbinds shared libraries during program execution. Debugging support for dlopen() and dlclose() lets you step into a function or set a breakpoint in functions in a dynamically shared library just as you can in a library linked when the program is started.

However, there are exceptions. dbx is unable to place breakpoints in loadobjects that have not been loaded (by, for example, using dlopen():

• You cannot set a breakpoint in a library loaded by dlopen() before that library is loaded by dlopen().

• You cannot set a breakpoint in a filter library loaded by dlopen() until the first function in it is called.

You can put the names of such loadobjects on the preload list with the loadobject command (see loadobject Command).

dbx does not forget about a loadobject that was loaded using dlopen(). For example, a breakpoint set in a freshly loaded loadobject remains until the next run command, or even if the loadobject is unloaded with dlclose() and then subsequently loaded with dlopen() again.