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how to auto load a dynamic library
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dladdr(3C) dladdr(3C) NAME
dladdr() - get the symbolic information for an address SYNOPSIS
[flag]... cfile ... [library]... Multithread Usage This routine is thread-safe. DESCRIPTION
is one of a family of routines that give the user direct access to the dynamic linking facilities (using the option on the compiler or com- mand line). allows a process to obtain information about the symbol that most closely defines a given address. determines whether the specified address is located within one of the load modules (executable or shared libraries) that make up the process' address space. An address is deemed to fall within a load module when it is between the base address at which the load module was mapped and the highest vir- tual address mapped for that load module, inclusive. If a load module fits this criteria, its dynamic symbol table is searched to locate the nearest symbol to the specified address. The nearest symbol is the one whose value is equal to, or closest to but less than the speci- fied address. dlip is a pointer to a structure. The structure must be allocated by the user. The structure members are set by if the specified address falls within one of the load modules. The structure contains the following members: The fields of the structure contain the following: dli_fname Pointer to the filename of the load module containing the address. The contents of this memory location can change between calls to dli_fbase Handle to the load module. This can be used as the first argument to dli_sname Pointer to the name of the nearest symbol to the specified address. This symbol either has the same address, or is the nearest symbol with a lower address. The contents of this memory location can change between calls to dli_saddr Actual address of the nearest symbol. For code symbols, it contains the address of the OPD (Official Plabel Descrip- tor) for the nearest code symbol. dli_size (ELF process only) Size of the nearest symbol as defined in the dynamic symbol table. dli_bind (ELF process only) Binding attribute of the nearest symbol as defined in the dynamic symbol table. The values for this are those used for a symbol's binding in the ELF symbol table (see dli_type Type of the nearest symbol. For ELF process, this is the same as the value for type in the dynamic symbol table. The values for this are those used for a symbol's type in the ELF symbol table (see For SOM process, this can have the value or as defined in RETURN VALUE
If the specified address does not fall within one of the load modules, is returned; the contents of the structure are not modified. Other- wise, a non-zero value is returned and the fields of the structure are set. DIAGNOSTICS
If no symbol is found within the load module containing address whose value is less than or equal to address, the dli_sname, dli_saddr, and dli_size fields are set to the dli_bind field is set to and the dli_type field is set to For only a subset of externally visible symbols are typically exported: specifically those referenced by the load modules with which the is linked. The exact set of exported symbols for any shared library or the can be controlled using the linker (see ld(1)). ERRORS
If fails, a subsequent call to returns one of the following values: Invalid symbol address in load module. Cannot apply relocation in library. Address not found in any load module. Out of memory. failed on entry to or exit from failed on exit from failed on entry to SEE ALSO
cc(1), ld(1), sh(1), exec(2), dlclose(3C), dlerrno(3C), dlerror(3C), dlsym(3C). Texts and Tutorials (See the option) (See manuals(5) for ordering information) dladdr(3C)
