如何编译这个C程序？
当我输入gcc gprof-helper.c来编译程序时，我得到以下错误：
gprof-helper.c: In function `wooinit': gprof-helper.c:38: error: `RTLD_NEXT' undeclared (first use in this function) gprof-helper.c:38: error: (Each undeclared identifier is reported only once gprof-helper.c:38: error: for each function it appears in.) 这是程序文件：
#define _GNU_SOURCE #include #include #include #include #include static void * wrapper_routine(void *); /* Original pthread function */ static int (*pthread_create_orig)(pthread_t *__restrict, __const pthread_attr_t *__restrict, void *(*)(void *), void *__restrict) = NULL; /* Library initialization function */ void wooinit(void) __attribute__((constructor)); void wooinit(void) { pthread_create_orig = dlsym(RTLD_NEXT, "pthread_create"); fprintf(stderr, "pthreads: using profiling hooks for gprof\n"); if(pthread_create_orig == NULL) { char *error = dlerror(); if(error == NULL) { error = "pthread_create is NULL"; } fprintf(stderr, "%s\n", error); exit(EXIT_FAILURE); } } /* Our data structure passed to the wrapper */ typedef struct wrapper_s { void * (*start_routine)(void *); void * arg; pthread_mutex_t lock; pthread_cond_t wait; struct itimerval itimer; } wrapper_t; /* The wrapper function in charge for setting the itimer value */ static void * wrapper_routine(void * data) { /* Put user data in thread-local variables */ void * (*start_routine)(void *) = ((wrapper_t*)data)->start_routine; void * arg = ((wrapper_t*)data)->arg; /* Set the profile timer value */ setitimer(ITIMER_PROF, &((wrapper_t*)data)->itimer, NULL); /* Tell the calling thread that we don't need its data anymore */ pthread_mutex_lock(&((wrapper_t*)data)->lock); pthread_cond_signal(&((wrapper_t*)data)->wait); pthread_mutex_unlock(&((wrapper_t*)data)->lock); /* Call the real function */ return start_routine(arg); } /* Our wrapper function for the real pthread_create() */ int pthread_create(pthread_t *__restrict thread, __const pthread_attr_t *__restrict attr, void * (*start_routine)(void *), void *__restrict arg) { wrapper_t wrapper_data; int i_return; /* Initialize the wrapper structure */ wrapper_data.start_routine = start_routine; wrapper_data.arg = arg; getitimer(ITIMER_PROF, &wrapper_data.itimer); pthread_cond_init(&wrapper_data.wait, NULL); pthread_mutex_init(&wrapper_data.lock, NULL); pthread_mutex_lock(&wrapper_data.lock); /* The real pthread_create call */ i_return = pthread_create_orig(thread, attr, &wrapper_routine, &wrapper_data); /* If the thread was successfully spawned, wait for the data * to be released */ if(i_return == 0) { pthread_cond_wait(&wrapper_data.wait, &wrapper_data.lock); } pthread_mutex_unlock(&wrapper_data.lock); pthread_mutex_destroy(&wrapper_data.lock); pthread_cond_destroy(&wrapper_data.wait); return i_return; }
我该如何摆脱这些错误？
自远古以来， RTLD_NEXT已在glibc中推出。
您是在Linux（或基于glibc）系统上构建的吗？ 听起来不像。
更新：
RTLD_NEXT是glibc 扩展 。 你不能在cygwin上使用它，因为cygwin ！= glibc 。
据我所知， cygwin也不支持LD_PRELOAD ，所以即使你成功构建了这个库，它也不会非常有用。