diff options
Diffstat (limited to 'man3/dlopen.3')
| -rw-r--r-- | man3/dlopen.3 | 20 |
1 files changed, 10 insertions, 10 deletions
diff --git a/man3/dlopen.3 b/man3/dlopen.3 index 90c365a65..a21e6e1b4 100644 --- a/man3/dlopen.3 +++ b/man3/dlopen.3 @@ -560,7 +560,7 @@ $ \fB./a.out\fP #include <dlfcn.h> #include <stdio.h> #include <stdlib.h> - +\& #include <gnu/lib\-names.h> /* Defines LIBM_SO (which will be a string such as "libm.so.6") */ int @@ -569,27 +569,27 @@ main(void) void *handle; double (*cosine)(double); char *error; - +\& handle = dlopen(LIBM_SO, RTLD_LAZY); if (!handle) { fprintf(stderr, "%s\en", dlerror()); exit(EXIT_FAILURE); } - +\& dlerror(); /* Clear any existing error */ - +\& cosine = (double (*)(double)) dlsym(handle, "cos"); - +\& /* According to the ISO C standard, casting between function pointers and \[aq]void *\[aq], as done above, produces undefined results. POSIX.1\-2001 and POSIX.1\-2008 accepted this state of affairs and proposed the following workaround: - +\& *(void **) (&cosine) = dlsym(handle, "cos"); - +\& This (clumsy) cast conforms with the ISO C standard and will avoid any compiler warnings. - +\& The 2013 Technical Corrigendum 1 to POSIX.1\-2008 improved matters by requiring that conforming implementations support casting \[aq]void *\[aq] to a function pointer. Nevertheless, some compilers @@ -598,13 +598,13 @@ main(void) .\" http://pubs.opengroup.org/onlinepubs/009695399/functions/dlsym.html#tag_03_112_08 .\" http://pubs.opengroup.org/onlinepubs/9699919799/functions/dlsym.html#tag_16_96_07 .\" http://austingroupbugs.net/view.php?id=74 - +\& error = dlerror(); if (error != NULL) { fprintf(stderr, "%s\en", error); exit(EXIT_FAILURE); } - +\& printf("%f\en", (*cosine)(2.0)); dlclose(handle); exit(EXIT_SUCCESS); |