*/

printf("1.0in = %5.2fcm\n", (*in_to_cm)(1.0)); printf("1.0gal = %5.2fl\n", (*gal_to_l)(1.0)); printf("1.0oz = %5.2fg\n", (*oz_to_g)(1.0)); /*

*Call routines from libtwo.so:

*/

(*foo)();

(*bar)();

/*

*Unload the libraries so we can see messages displayed by initializer:

*/

shl_unload(hndl_units); shl_unload(hndl_two);

}

Following is the command to create the executable testlib2:

$ cc -Aa -Wl,-E -o testlib2 testlib2.c init.c -ldld

Note that the -Wl,-Eoption is required to cause the linker to export all symbols from the main program. This allows the shared libraries to find the _INITIALIZER function in the main executable. The output from running testlib2 is given below:

Output of testlib2

$ cc -Aa testlib2.c -o testlib2 -ldld $ testlib2

libunits.so loaded libtwo.so loaded 1.0in = 2.54cm 1.0gal = 3.79l 1.0oz = 28.35g foo called

bar called libunits.so unloaded libtwo.so unloaded

The dlopen Shared Library Management Routines

This section describes the dl* family of shared library management routines. All these routines are available in IPF/PA-64 mode. Support for the following routines is available in PA-32 mode:

•dlopen

•dlclose

•dlsym

•dlerror

The dlopen Routine

The dlopen routine opens a shared library.

Syntax

void *dlopen(const char *file, int mode);

void *dlopene(const char *file, int mode, struct dlopen_opts *opts);

148 Shared Library Management Routines