以Hello World程序为例：

#import <foundation/foundation.h>


@interface SaySomething :NSObject
- (void) say:(NSString *)phrase;
@end

@implementation SaySomething

- (void) say:(NSString *)phrase{
    printf("%s\n", [phrase UTF8String]);
}

@end

int main(){
    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
    SaySomething *saySomething = [[SaySomething alloc] init];
    [saySomething say:@"Hello World!"];
    [saySomething release];
    [pool release];
    return 0;
}</foundation>

#import <foundation/foundation.h>

@interface SaySomething :NSObject
- (void) say:(NSString *)phrase;
@end

@implementation SaySomething

- (void) say:(NSString *)phrase{
    printf("%s\n", [phrase UTF8String]);
}

@end

//int main(){
//    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
//    SaySomething *saySomething = [[SaySomething alloc] init];
//    [saySomething say:@"Hello World!"];
//    [saySomething release];
//    [pool release];
//    return 0;
//}

int main(){
    objc_msgSend(objc_msgSend(objc_getClass("NSAutoreleasePool"), NSSelectorFromString(@"alloc")), NSSelectorFromString(@"init"));
    objc_msgSend(objc_msgSend(objc_msgSend(objc_getClass("SaySomething"), NSSelectorFromString(@"alloc")), NSSelectorFromString(@"init")), NSSelectorFromString(@"say:"), @"Hello World!");
    return 0;
}

iMAC:ios$ /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/arm-apple-darwin10-llvm-gcc-4.2 -o hello hello.m -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS6.0.sdk/ -framework Foundation -lobjc

iMAC:ios$ otool -L hello
hello:
/System/Library/Frameworks/Foundation.framework/Foundation (compatibility version 300.0.0, current version 992.0.0)
/usr/lib/libobjc.A.dylib (compatibility version 1.0.0, current version 228.0.0) //包含这个文件则为objective-c编译的文件
/usr/lib/libgcc_s.1.dylib (compatibility version 1.0.0, current version 7.0.0)
/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 173.8.0)
/System/Library/Frameworks/CoreFoundation.framework/CoreFoundation (compatibility version 150.0.0, current version 793.0.0)

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