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dyld: lazy bind: client:0x107575050 = libdyld.dylib:_dlopen, *0x107575050 = 0x7FFF88740922
dyld: bind: libPerson.dylib:0x1075A9000 = libdyld.dylib:dyld_stub_binder, *0x1075A9000 = 0x7FFF887406A0
dyld: bind: libPerson.dylib:0x1075A9220 = libobjc.A.dylib:__objc_empty_cache, *0x1075A9220 = 0x7FFF7890EC10
dyld: bind: libPerson.dylib:0x1075A9248 = libobjc.A.dylib:__objc_empty_cache, *0x1075A9248 = 0x7FFF7890EC10
dyld: bind: libPerson.dylib:0x1075A9228 = libobjc.A.dylib:__objc_empty_vtable, *0x1075A9228 = 0x7FFF7890CF60
dyld: bind: libPerson.dylib:0x1075A9250 = libobjc.A.dylib:__objc_empty_vtable, *0x1075A9250 = 0x7FFF7890CF60
dyld: bind: libPerson.dylib:0x1075A9218 = CoreFoundation:_OBJC_CLASS_$_NSObject, *0x1075A9218 = 0x7FFF77C40BA8
dyld: bind: libPerson.dylib:0x1075A9238 = CoreFoundation:_OBJC_METACLASS_$_NSObject, *0x1075A9238 = 0x7FFF77C40B80
dyld: bind: libPerson.dylib:0x1075A9240 = CoreFoundation:_OBJC_METACLASS_$_NSObject, *0x1075A9240 = 0x7FFF77C40B80
dyld: bind: libPerson.dylib:0x1075A9260 = CoreFoundation:___CFConstantStringClassReference, *0x1075A9260 = 0x7FFF77C72760
dyld: bind: libPerson.dylib:0x1075A9280 = CoreFoundation:___CFConstantStringClassReference, *0x1075A9280 = 0x7FFF77C72760

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symbol_pointer = dlsym(library_handle, "my_symbol")

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#include <stdio.h>
extern char* A_name();          // libArt.dylib
extern char* dependencies();    // libBus.dylib
 
int main(void) {
    printf("[%s] libArt.A_name() = %s\n", __FILE__, A_name());
    printf("[%s] libBus.dependencies() = %s\n", __FILE__, dependencies());
}

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#include <stdio.h>
#include <dlfcn.h>
 
int main(void) {
    void* Bus1a_handle = dlopen("libBus1a.dylib", RTLD_LOCAL);
    if (Bus1a_handle) {
        char* (*b1a_name)() = dlsym(Bus1a_handle, "B1a_name");
        if (b1a_name) {
            printf("[%s] libBus1a.B1a_name() = %s\n",
                __FILE__, b1a_name());
        }
    }
    else {
        printf("[%s] Unable to open libBus1a.dylib: %s\n",
            __FILE__, dlerror());
    }
    dlclose(Bus1a_handle);
}

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#include <string.h>
static char* k_lib_name = "libBus";
char* dependencies(void) {
    char _dependencies[50] = "";
    strcpy(_dependencies, k_lib_name);
    char* (*next_dependencies)() =
        dlsym(RTLD_NEXT, "dependencies");// look for next definition
    if (next_dependencies) {
        strncat(_dependencies, ", ",
            sizeof(_dependencies) - strlen(_dependencies) - 1);
        strncat(_dependencies, next_dependencies(),
            sizeof(_dependencies) - strlen(_dependencies) - 1);
    }
    return strdup(_dependencies);
}

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#include <stdio.h>
extern char* dependencies();    // libBus.dylib
 
int main(void) {
    printf("[%s] libBus.dependencies() = %s\n",
        __FILE__, dependencies());
}

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nm -m <client_file> | grep weak

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/* File: Person.h */
#define WEAK_IMPORT __attribute__((weak_import))
char* name(void);
void set_name(char* name);
WEAK_IMPORT
void clear_name(void);

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/ Clear the 'name' property.
if (clear_name) {
    clear_name();
}
else {
    set_name(" ");
}

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[Ratings/1.0]% make dylib
clang -dynamiclib -std=gnu99 Ratings.c -current_version 1.0 -compatibility_version 1.0 -fvisibility=hidden -o libRatings.A.dylib

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/* Dependent.c
 * Tests libRatings.A.dylib 1.0 as a dependent library.
 *****************************************************/
 
#include <stdio.h>
#include <string.h>
#include "Ratings.h"
 
#define PASSFAIL "Passed":"Failed"
#define UNTST "Untested"
 
int main(int argc, char **argv) {
    printf("[start_test]\n");
 
    // Setup.
    addRating(NULL);
    addRating("");
    addRating("*");
    addRating("**");
    addRating("***");
    addRating("*****");
    addRating("*****");
 
    // ratings.
    printf("[%s] ratings(): %s\n",
        __FILE__, (ratings() == 6? PASSFAIL));
 
    // meanRating.
    printf("[%s] meanRating(): %s\n",
        __FILE__, (strcmp(meanRating(), "**") == 0)? PASSFAIL);
 
    // clearRatings.
    clearRatings();
    printf("[%s] clearRatings(): %s\n",
        __FILE__, (ratings() == 0? PASSFAIL));
 
    printf("[end_test]\n");
    return 0;
}

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clang Dependent.c libRatings.A.dylib -o Dependent

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> ./Dependent
[Ratings.c] initializer()
[start_test]
[Dependent.c] ratings(): Passed
[Dependent.c] meanRating(): Passed
[Dependent.c] clearRatings(): Passed
[end_test]
[Ratings.c] finalizer()

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[Ratings/1.0]% make runtime
clang Runtime.c -o Runtime

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> ./Runtime
[start_test]
[Ratings.c] initializer()
[Runtime.c] dlopen("./libRatings.A.dylib", RTLD_NOW): Successful
[Runtime.c] dlsym(lib_handle, "addRating"): Successful
[Runtime.c] dlsym(lib_handle, "meanRating"): Successful
[Runtime.c] dlsym(lib_handle, "clearRatings"): Successful
[Runtime.c] dlsym(lib_handle, "ratings"): Successful
[Runtime.c] ratings(): Passed
[Runtime.c] meanRating(): Passed
[Runtime.c] clearRatings(): Passed
[Runtime.c] dlclose(lib_handle): Successful
[end_test]
[Ratings.c] finalizer()

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/* File: Ratings.h
 * Interface to libRatings.A.dylib 1.1.
 *************************************/
 
#define WEAK_IMPORT __attribute__((weak_import))
 
/* Adds 'rating' to the set.
 *      rating: Each character adds 1 to the numeric rating
 *      Example: "" = 0, "*" = 1, "**" = 2, "wer " = 4.
 */
void addRating(char* rating);
 
/* Returns the number of ratings in the set.
 */
int ratings(void);
 
/* Returns the mean rating of the set.
 */
char* meanRating(void);
 
/* Returns the medianRating of the set.
 */
WEAK_IMPORT
char *medianRating(void);                       // 1
 
/* Returns the most frequent rating of the set.
 */
WEAK_IMPORT
char *frequentRating(void);                     // 2
 
/* Clears the set.
 */
void clearRatings(void);

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/* File: Ratings.c
 * Compile with -fvisibility=hidden.
 **********************************/
 
#include "Ratings.h"
#include <Averages.h>
#include <stdio.h>
#include <string.h>
#include <float.h>
 
#define EXPORT __attribute__((visibility("default")))
#define MAX_NUMBERS 99
//#define MAX_NUMERIC_RATING 10               // published in Ratings.h
 
static char *_char_rating(float rating) {
    char result[10] = "";
    int int_rating = (int)(rating + 0.5);
    for (int i = 0; i < int_rating; i++) {
        strncat(result, "*", sizeof(result) - strlen(result) - 1);
    }
    return strdup(result);
}
 
EXPORT
void addRating(char *rating) {
    if (rating != NULL) {
        int numeric_rating = 0;
        int pos = 0;
        while (*rating++ != '\0' && pos++ < 5) {
            numeric_rating++;
        }
        add((float)numeric_rating);     // libAverages.A:add()
    }
}
 
EXPORT
char *meanRating(void) {
    return _char_rating(mean());        // libAverages.A:mean()
}
 
EXPORT
char *medianRating(void) {
    return _char_rating(median());      // libAverages.A:median()
}
 
EXPORT
char *frequentRating(void) {
    int lib_mode = mode();                // libAverages.A:mode()
    return _char_rating(lib_mode);
}
 
EXPORT
int ratings(void) {
    return count();                     // libAverages.A:count()
}
 
EXPORT
void clearRatings(void) {
    clear();                            // libAverages.A:clear()
}
 
/* Ratings.c revision history
 * 1. First version.
 * 2. Added medianRating, frequentRating.
 *    Removed initializer, finalizer.
 */
 

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/* Runtime.c
 * Tests libRatings.A.dylib 1.1 as a runtime-loaded library.
 **********************************************************/
 
#include <stdio.h>
#include <stdlib.h>
#include <dlfcn.h>
#include <string.h>
#include "Ratings.h"
 
#define PASSFAIL "Passed":"Failed"
#define UNTST "Untested"
 
int main(int argc, char** argv) {
    printf("[start_test]\n");
 
    // Open the library.
    char *lib_name = "./libRatings.A.dylib";
    void *lib_handle = dlopen(lib_name, RTLD_NOW);
    if (lib_handle) {
        printf("[%s] dlopen(\"%s\", RTLD_NOW): Successful\n", __FILE__, lib_name);
    }
    else {
        printf("[%s] Unable to open library: %s\n",
            __FILE__, dlerror());
        exit(EXIT_FAILURE);
    }
 
    // Get the function addresses.
    void (*addRating)(char*) = dlsym(lib_handle, "addRating");
    if (addRating) {
        printf("[%s] dlsym(lib_handle, \"addRating\"): Successful\n", __FILE__);
    }
    else {
        printf("[%s] Unable to get symbol: %s\n",
            __FILE__, dlerror());
        exit(EXIT_FAILURE);
    }
    char* (*meanRating)(void) = dlsym(lib_handle, "meanRating");
    if (meanRating) {
        printf("[%s] dlsym(lib_handle, \"meanRating\"): Successful\n", __FILE__);
    }
    else {
        printf("[%s] Unable to get symbol: %s\n",
            __FILE__, dlerror());
        exit(EXIT_FAILURE);
    }
    void (*clearRatings)(void) = dlsym(lib_handle, "clearRatings");
    if (clearRatings) {
        printf("[%s] dlsym(lib_handle, \"clearRatings\"): Successful\n", __FILE__);
    }
    else {
        printf("[%s] Unable to get symbol: %s\n",
            __FILE__, dlerror());
        exit(EXIT_FAILURE);
    }
    int (*ratings)(void) = dlsym(lib_handle, "ratings");
    if (ratings) {
        printf("[%s] dlsym(lib_handle, \"ratings\"): Successful\n", __FILE__);
    }
    else {
        printf("[%s] Unable to get symbol: %s\n",
            __FILE__, dlerror());
        exit(EXIT_FAILURE);
    }
    char *(*medianRating)(void) = dlsym(lib_handle, "medianRating");        // weak import
    char *(*frequentRating)(void) = dlsym(lib_handle, "frequentRating");    // weak import
 
    // Setup.
    addRating(NULL);
    addRating("");
    addRating("*");
    addRating("**");
    addRating("***");
    addRating("*****");
    addRating("*****");
 
    // ratings.
    printf("[%s] ratings(): %s\n", __FILE__, (ratings() == 6? PASSFAIL));
 
    // meanRating.
    printf("[%s] meanRating(): %s\n", __FILE__, (strcmp(meanRating(), "**") == 0)? PASSFAIL);
 
    // medianRating.
    if (medianRating) {
        printf("[%s] medianRating(): %s\n", __FILE__, (strcmp(medianRating(), "**") == 0? PASSFAIL));
    }
    else {
        printf("[%s] medianRating(): %s\n", __FILE__, UNTST);
    }
 
    // frequentRating.
 
    if (frequentRating) {
        char* test_rating = "*****";
        int test_rating_size = sizeof(test_rating);
        printf("[%s] frequentRating(): %s\n", __FILE__, strncmp(test_rating, frequentRating(), test_rating_size) == 0? PASSFAIL);
    }
    else {
        printf("[%s] mostFrequentRating(): %s\n", __FILE__, UNTST);
    }
 
    // clearRatings.
    clearRatings();
    printf("[%s] clearRatings(): %s\n", __FILE__, (ratings() == 0? PASSFAIL));
 
    // Close the library.
    if (dlclose(lib_handle) == 0) {
        printf("[%s] dlclose(lib_handle): Successful\n", __FILE__);
    }
    else {
        printf("[%s] Unable to open close: %s\n",
            __FILE__, dlerror());
    }
 
    printf("[end_test]\n");
    return 0;
}

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[Ratings/1.1]% make dylib
clang -dynamiclib -std=gnu99 Ratings.c -I<user_home>/include <user_home>/lib/libAverages.dylib -current_version 1.1 -compatibility_version 1.0 -fvisibility=hidden -o libRatings.A.dylib

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/* Dependent.c
 * Tests libRatings.A.dylib 1.1 as a dependent library.
 *****************************************************/
 
#include <stdio.h>
#include <string.h>
#include "Ratings.h"
 
#define PASSFAIL "Passed":"Failed"
#define UNTST "Untested"
 
int main(int argc, char **argv) {
    printf("[start_test]\n");
 
    // Setup.
    addRating(NULL);
    addRating("");
    addRating("*");
    addRating("**");
    addRating("***");
    addRating("*****");
    addRating("*****");
 
    // ratings.
    printf("[%s] ratings(): %s\n",
        __FILE__, (ratings() == 6? PASSFAIL));
 
    // meanRating.
    printf("[%s] meanRating(): %s\n",
        __FILE__, (strcmp(meanRating(), "**") == 0)? PASSFAIL);
 
    // medianRating.
    if (medianRating) {                         // 1
        printf("[%s] medianRating(): %s\n",
            __FILE__, (strcmp(medianRating(), "**") == 0? PASSFAIL));
    }
    else {
        printf("[%s] medianRating(): %s\n", __FILE__, UNTST);
    }
 
    // frequentRating.
    if (frequentRating) {                         // 2
 
        char *test_rating = "*****";
        int test_rating_size = sizeof(test_rating);
        printf("[%s] frequentRating(): %s\n",
            __FILE__, strncmp(test_rating, frequentRating(),
            test_rating_size) == 0? PASSFAIL);
    }
    else {
        printf("[%s] mostFrequentRating(): %s\n",
            __FILE__, UNTST);
    }
 
    // clearRatings.
    clearRatings();
    printf("[%s] clearRatings(): %s\n",
        __FILE__, (ratings() == 0? PASSFAIL));
 
    printf("[end_test]\n");
    return 0;
}

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[Avarages/1.1]% make install

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[Ratings/1.1]% make
clang -dynamiclib -std=gnu99 Ratings.c -I<user_home>/include <user_home>/lib/libAverages.dylib -current_version 1.1 -compatibility_version 1.0 -fvisibility=hidden -o libRatings.A.dylib
clang Dependent.c libRatings.A.dylib <user_home>/lib/libAverages.dylib -o Dependent
clang Runtime.c -o Runtime

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> ./Dependent
[start_test]
[Dependent.c] ratings(): Passed
[Dependent.c] meanRating(): Passed
[Dependent.c] medianRating(): Passed
[Dependent.c] frequentRating(): Passed
[Dependent.c] clearRatings(): Passed
[end_test]

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/* Runtime.c
 * Tests libRatings.A.dylib 1.1 as a runtime-loaded library.
 **********************************************************/
 
#include <stdio.h>
#include <stdlib.h>
#include <dlfcn.h>
#include <string.h>
#include "Ratings.h"
 
#define PASSFAIL "Passed":"Failed"
#define UNTST "Untested"
 
int main(int argc, char **argv) {
    printf("[start_test]\n");
 
    // Open the library.
    char* lib_name = "./libRatings.A.dylib";
    void* lib_handle = dlopen(lib_name, RTLD_NOW);
    if (lib_handle) {
        printf("[%s] dlopen(\"%s\", RTLD_NOW): Successful\n", __FILE__, lib_name);
    }
    else {
        printf("[%s] Unable to open library: %s\n",
            __FILE__, dlerror());
        exit(EXIT_FAILURE);
    }
 
    // Get the function addresses.
    void (*addRating)(char*) = dlsym(lib_handle, "addRating");
    if (addRating) {
        printf("[%s] dlsym(lib_handle, \"addRating\"): Successful\n", __FILE__);
    }
    else {
        printf("[%s] Unable to get symbol: %s\n",
            __FILE__, dlerror());
        exit(EXIT_FAILURE);
    }
    char* (*meanRating)(void) = dlsym(lib_handle, "meanRating");
    if (meanRating) {
        printf("[%s] dlsym(lib_handle, \"meanRating\"): Successful\n", __FILE__);
    }
    else {
        printf("[%s] Unable to get symbol: %s\n",
            __FILE__, dlerror());
        exit(EXIT_FAILURE);
    }
    void (*clearRatings)(void) = dlsym(lib_handle, "clearRatings");
    if (clearRatings) {
        printf("[%s] dlsym(lib_handle, \"clearRatings\"): Successful\n", __FILE__);
    }
    else {
        printf("[%s] Unable to get symbol: %s\n",
            __FILE__, dlerror());
        exit(EXIT_FAILURE);
    }
    int (*ratings)(void) = dlsym(lib_handle, "ratings");
    if (ratings) {
        printf("[%s] dlsym(lib_handle, \"ratings\"): Successful\n", __FILE__);
    }
    else {
        printf("[%s] Unable to get symbol: %s\n",
            __FILE__, dlerror());
        exit(EXIT_FAILURE);
    }
    char* (*medianRating)(void) = dlsym(lib_handle, "medianRating");        // weak import
    char* (*frequentRating)(void) = dlsym(lib_handle, "frequentRating");    // weak import
 
    // Setup.
    addRating(NULL);
    addRating("");
    addRating("*");
    addRating("**");
    addRating("***");
    addRating("*****");
    addRating("*****");
 
    // ratings.
    printf("[%s] ratings(): %s\n", __FILE__, (ratings() == 6? PASSFAIL));
 
    // meanRating.
    printf("[%s] meanRating(): %s\n", __FILE__, (strcmp(meanRating(), "**") == 0)? PASSFAIL);
 
    // medianRating.
    if (medianRating) {
        printf("[%s] medianRating(): %s\n", __FILE__, (strcmp(medianRating(), "**") == 0? PASSFAIL));
    }
    else {
        printf("[%s] medianRating(): %s\n", __FILE__, UNTST);
    }
 
    // frequentRating.
    if (frequentRating) {
        char* mfr = "*****";
        printf("[%s] frequentRating(): %s\n", __FILE__, strncmp(mfr, frequentRating(), sizeof(mfr)) == 0? PASSFAIL);
    }
    else {
        printf("[%s] mostFrequentRating(): %s\n", __FILE__, UNTST);
    }
 
    // clearRatings.
    clearRatings();
    printf("[%s] clearRatings(): %s\n", __FILE__, (ratings() == 0? PASSFAIL));
 
    // Close the library.
    if (dlclose(lib_handle) == 0) {
        printf("[%s] dlclose(lib_handle): Successful\n", __FILE__);
    }
    else {
        printf("[%s] Unable to open close: %s\n",
            __FILE__, dlerror());
    }
 
    printf("[end_test]\n");
    return 0;
}

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[Ratings/1.1]% ./Runtime
[start_test]
[Runtime.c] dlopen("./libRatings.A.dylib", RTLD_NOW): Successful
[Runtime.c] dlsym(lib_handle, "addRating"): Successful
[Runtime.c] dlsym(lib_handle, "meanRating"): Successful
[Runtime.c] dlsym(lib_handle, "clearRatings"): Successful
[Runtime.c] dlsym(lib_handle, "ratings"): Successful
[Runtime.c] ratings(): Passed
[Runtime.c] meanRating(): Passed
[Runtime.c] medianRating(): Passed
[Runtime.c] frequentRating(): Passed
[Runtime.c] clearRatings(): Passed
[Runtime.c] dlclose(lib_handle): Successful
[end_test]

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[           ]% cd <companion_dir>/Ratings/1.1
[Ratings/1.1]% make
[Ratings/1.1]% cd ../1.0
[Ratings/1.0]% make
[Ratings/1.0]% cp libRatings.A.dylib ../1.1
[Ratings/1.0]% cd ../1.1

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[Ratings/1.1]% ./Runtime
[start_test]
[Ratings.c] initializer()
[Runtime.c] dlopen("./libRatings.A.dylib", RTLD_NOW): Successful
[Runtime.c] dlsym(lib_handle, "addRating"): Successful
[Runtime.c] dlsym(lib_handle, "meanRating"): Successful
[Runtime.c] dlsym(lib_handle, "clearRatings"): Successful
[Runtime.c] dlsym(lib_handle, "ratings"): Successful
[Runtime.c] ratings(): Passed
[Runtime.c] meanRating(): Passed
[Runtime.c] medianRating(): Untested
[Runtime.c] mostFrequentRating(): Untested
[Runtime.c] clearRatings(): Passed
[Runtime.c] dlclose(lib_handle): Successful
[end_test]
[Ratings.c] finalizer()

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/* File: StarMeals.c
 * Uses functions in libRatings.A.dylib.
 **************************************/
 
#include <stdio.h>
#include <string.h>
#include <Ratings.h>
 
#define MAX_NAMES 100
#define MAX_NAME_LENGTH 30
#define MAX_RATING_LENGTH 5
 
static char* name_list[MAX_NAMES];
static char* rating_list[MAX_NAMES];
static int names = 0;
 
void addNameAndRating(char* name, char* rating) {
    name_list[names] = strdup(name);
    rating_list[names] = (strlen(rating) > MAX_RATING_LENGTH)? "*****" : strdup(rating);
    names++;
}
 
void test_data(void) {
    addNameAndRating("Spinach", "*");
    addNameAndRating("Cake", "****");
    addNameAndRating("Steak", "****");
    addNameAndRating("Caviar", "*");
    addNameAndRating("Broccoli", "****");
    addNameAndRating("Gagh", "*****");
    addNameAndRating("Chicken", "*****");
}
 
int main(int argc, char* argv[]) {
    int test_mode = 0;
    if (argc == 2) {
        if (strcmp(argv[1], "test") == 0) {
            test_mode = 1;
            printf("[start_test]\n");
            test_data();
        }
    }
    else {
        printf("Enter meal names and ratings in the form <name> <rating>.\n");
        printf("No spaces are allowed in the name and the rating.\n");
        printf("The rating can be * through *****.\n");
        printf("To finish, enter \"end\" for a meal name.\n");
        while (names < MAX_NAMES) {
            char name[MAX_NAME_LENGTH];
            char rating[MAX_RATING_LENGTH + 1];
            printf("\nName and rating: ");
            scanf("%s", &name);
            if (strcmp(name, "end") == 0) {
                break;
            }
            scanf("%s", rating);
            addNameAndRating(name, rating);
        }
        printf("\n");
    }
 
    if (names) {
        // Print data entered and call libRatings.addRating().
        printf("This is the data you entered:\n");
        for (int i = 0; i < names; i++) {
            printf("%s (%s)\n", name_list[i], rating_list[i]);
            addRating(rating_list[i]);
        }
 
        // Print statistical information.
        printf("\nThe mean rating is %s\n", meanRating()); // 1
        if (medianRating) {                                // 2
            printf("The median rating is %s\n", medianRating());
        }
        if (frequentRating) {                              // 3
            printf("The most frequent rating is %s\n", frequentRating());
        }
 
        //printf("\n");
    }
 
    if (test_mode) {
        printf("[end_test]\n");
    }
    return 0;
}

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[StarMeals]% make
clang -std=gnu99 StarMeals.c <user_home>/lib/libRatings.dylib <user_home>/lib/libAverages.dylib -o StarMeals

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> ./StarMeals test
start_test
This is the data you entered:
Spinach (*)
Cake (****)
Steak (****)
Caviar (*)
Broccoli (****)
Gagh (*****)
Chicken (*****)
 
The mean rating is ***
The medianRating is ****
The most frequent rating is ****
[end_test]

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/* File: StarMeals2.c
 * Uses functions in libRatings.A.dylib.
 **************************************/
 
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <dlfcn.h>
#include <Ratings.h>
 
#define MAX_NAMES 100
#define MAX_NAME_LENGTH 30
#define MAX_RATING_LENGTH 5
 
static char *name_list[MAX_NAMES];
static char *rating_list[MAX_NAMES];
static int names = 0;
 
void addNameAndRating(char *name, char *rating) {
    name_list[names] = strdup(name);
    rating_list[names] =
        (strlen(rating) > MAX_RATING_LENGTH)?
        "*****" : strdup(rating);
    names++;
}
 
void test_data(void) {
    addNameAndRating("Spinach", "*");
    addNameAndRating("Cake", "****");
    addNameAndRating("Steak", "****");
    addNameAndRating("Caviar", "*");
    addNameAndRating("Broccoli", "****");
    addNameAndRating("Gagh", "*****");
    addNameAndRating("Chicken", "*****");
}
 
int main(int argc, char *argv[]) {
    int test_mode = 0;
    if (argc == 2) {
        if (strcmp(argv[1], "test") == 0) {
            test_mode = 1;
            printf("[start_test]\n");
            test_data();
        }
    }
    else {
        printf("Enter restaurant names and ratings in the form <name> <rating>.\n");
        printf("No spaces are allowed in the name and the rating.\n");
        printf("The rating can be * through *****.\n");
        printf("To finish, enter \"end\" for a restaurant name.\n");
        while (names < MAX_NAMES) {
            char name[MAX_NAME_LENGTH];
            char rating[MAX_RATING_LENGTH + 1];
            printf("\nName and rating: ");
            scanf("%s", &name);
            if (strcmp(name, "end") == 0) {
                break;
            }
            scanf("%s", rating);
            addNameAndRating(name, rating);
        }
        printf("\n");
    }
 
    if (names) {
        // Open Ratings library.
        void* lib_handle = dlopen("libRatings.A.dylib", RTLD_LOCAL|RTLD_LAZY);
        if (!lib_handle) {
            printf("[%s] Unable to load library: %s\n", __FILE__, dlerror());
            exit(EXIT_FAILURE);
        }
 
        // Print data entered and call libRatings.A:addRating().
        void (*addRating)(char*) = dlsym(lib_handle, "addRating");
        if (!addRating) {       // addRating is guaranteed to exist in libRatings.A.dylib
            printf("[%s] Unable to get symbol: %s\n", __FILE__, dlerror());
            exit(EXIT_FAILURE);
        }
        printf("This is the data you entered:\n");
        for (int i = 0; i < names; i++) {
            printf("%s (%s)\n", name_list[i], rating_list[i]);
            addRating(rating_list[i]);
        }
 
        // Print statistical information.
        char *(*meanRating)(void) = dlsym(lib_handle, "meanRating");
        if (!meanRating) {      // meanRating is guaranteed to exist in libRatings.A.dylib
            printf("[%s] Unable to get symbol: %s\n", __FILE__, dlerror());
            exit(EXIT_FAILURE);
        }
        printf("\nThe mean rating is %s\n", meanRating());
 
        char *(*medianRating)(void) = dlsym(lib_handle, "medianRating");
        if (medianRating) {     // Backwards compatibility with Ratings 1.0
            printf("The median rating is %s\n", medianRating());
        }
        char *(*frequentRating)(void) = dlsym(lib_handle, "frequentRating");
        if (frequentRating) {   // Backwards compatibility with Ratings 1.0
            printf("The most frequent rating is %s\n", frequentRating());
        }
 
        // Close Ratings library
        if (dlclose(lib_handle) != 0) {
            printf("[%s] Problem closing library: %s", __FILE__, dlerror());
        }
    }
 
    if (test_mode) {
        printf("[end_test]\n");
    }
    return 0;
}

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[StarMeals2]% make
clang -std=gnu99 StarMeals2.c -I<user_home>/include -o StarMeals2

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char *name(void) {
    static int name_calls = 0;
    printf("[STATS] name() has been called %i times\n", name_calls);
    char *(*next_name)(void) = dlsym(RTLD_NEXT, "name");
    return next_name();
}

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/* File: RatingsInterposed.h
 * Interface to the RatingsAsGrages dynamic library.
 **************************************************/
 
/* Adds 'grade' to the set.
 *      grade: Non-NULL string. Contains zero or
 *             one of these characters:
 *             A, B, C, D, F.
 *             Examples: "", "A", "B".
 */
void addRating(char* grade);
 
/* Returns the median grade.
 */
char *medianRating(void);
 
/* Returns the most frequent grade.
 */
char *frequentRating(void);
 
/* File: RatingsAsGrades.c
 * Compile with -fvisibility=hidden.
 ***********************************/
 
#include "RatingsAsGrades.h"
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <dlfcn.h>
 
#define EXPORT __attribute__((visibility("default")))
#define MAX_STAR_RATING_LEN 6
 
static char *_ratingAsGrade(char *rating) {
    int rating_length = strlen(rating);
    if (rating_length > MAX_STAR_RATING_LEN - 1) {
        rating_length = MAX_STAR_RATING_LEN - 1;
    }
    char grade;
    switch (rating_length) {
        case 5:
            grade = 'A';
            break;
        case 4:
            grade = 'B';
            break;
        case 3:
            grade = 'C';
            break;
        case 2:
            grade = 'D';
            break;
        case 1:
            grade = 'F';
            break;
        default:
            grade = '\0';
    }
    char char_grade[2] = { grade, '\0' };
    return strdup(char_grade);
}
 
// Interpose libRatings.B.dylib:addRating.
EXPORT
void addRating(char* grade) {
    char rating[MAX_STAR_RATING_LEN] = { '\0' };
    switch (*grade) {
        case 'A':
            strcat(rating, "*");
        case 'B':
            strcat(rating, "*");
        case 'C':
            strcat(rating, "*");
        case 'D':
            strcat(rating, "*");
        case 'F':
            strcat(rating, "*");
        default:
            ;
    }
    void (*next_addRating)(char *) =
dlsym(RTLD_NEXT, "addRating");
    if (next_addRating) {
        next_addRating(rating);
    }
    else {
        printf("[%s] Fatal problem: %s", __FILE__, dlerror());
    }
}
 
// Interpose libRatings.B.dylib:medianRating.
EXPORT
char *medianRating(void) {
    char medianGrade[2] = { '\0' };
    char *(*next_medianRating)(void) =
dlsym(RTLD_NEXT, "medianRating");
    if (next_medianRating) {
        strcpy(medianGrade,
_ratingAsGrade(next_medianRating()));
    }
    else {
        printf("[%s] Fatal problem: %s", __FILE__, dlerror());
        exit(EXIT_FAILURE);
    }
    return strdup(medianGrade);
}
 
// Interpose libRatings.B.dylib:frequentRating.
EXPORT
char *frequentRating(void) {
    char frequentGrade[2] = { '\0' };
    char *(*next_frequentRating)(void) =
        dlsym(RTLD_NEXT, "frequentRating");
    if (next_frequentRating) {
        strcpy(frequentGrade,
            _ratingAsGrade(next_frequentRating()));
    }
    else {
        printf("[%s] Fatal problem: %s", __FILE__, dlerror());
        exit(EXIT_FAILURE);
    }
    return strdup(frequentGrade);
 
}

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[Grades]% ./Grades test
[start_test]
This is the data you entered:
Eloise  (F)
Karla   (B)
Iva     (B)
Hilaire (F)
Jewel   (B)
Simone  (A)
Yvette  (A)
Renee   (A)
Mimi    (A)
 
The median grade is B
The most frequent grade is A
[end_test]

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@rpath/<path_to_dynamic_library>

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@loader_path/../Library/OpenSource
/usr/lib