Kenwood HP 9000 manual Bindnonfatal Modifier, Bindverbose Modifier, Bindfirst Modifier, 220

Shared Library Management Routines

The shl_load Shared Library Management Routines

}

/*

*Dynamically load the shared library using BIND_IMMEDIATE binding:

*/

lib_handle = shl_load( lib_path, BIND_IMMEDIATE, 0); if (lib_handle == NULL)

perror(“shl_load: error loading library”), exit(1); return lib_handle;

}

BIND_NONFATAL Modifier

If you load a shared library with the BIND_IMMEDIATE flag and the library contains unresolved symbols, the load fails and sets errno to ENOSYM. ORing BIND_NONFATAL with BIND_IMMEDIATE causes shl_load to allow the binding of unresolved symbols to be deferred if their later use can be detected — for example:

shl_t libH;

. . .

libH = shl_load("libxyz.sl", BIND_IMMEDIATE BIND_NONFATAL, 0);

However, data symbol binding cannot be deferred, so using the

BIND_NONFATAL modifier does not allow the binding of unresolved data symbols.

BIND_VERBOSE Modifier

If BIND_VERBOSE is ORed with the flags parameter, the dynamic loader displays messages for all unresolved symbols. This option is useful to see exactly which symbols cannot be bound. Typically, you would use this with BIND_IMMEDIATE to debug unresolved symbols — for example:

shl_t libH;

. . .

libH = shl_load("libxyz.sl", BIND_IMMEDIATE BIND_VERBOSE, 0);

BIND_FIRST Modifier

If BIND_FIRST is ORed with the flags parameter, the loaded library is inserted before all other loaded shared libraries in the symbol resolution search order. This has the same effect as placing the library first in the link order — that is, the library is searched before other libraries when resolving symbols. This is used with either BIND_IMMEDIATE or BIND_DEFERRED — for example:

shl_t libH;

. . .

libH = shl_load("libpdq.sl", BIND_DEFERRED BIND_FIRST, 0);

220 Chapter 6