Segmentation fault when attemping to print NSString as UTF8String

问题

I have the following objective-c snippet in my hello world example:

//hello.m

#import <Foundation/Foundation.h>
#import "hello.h"

void sayHello()
{
    #ifdef FRENCH
    NSString *helloWorld = @"Bonjour Monde!\n";
    #else
    NSString *helloWorld = @"Hello World\n";
    #endif
    printf("%s", [helloWorld UTF8String]);
}


//main.m
#import <Foundation/Foundation.h>
#import "hello.h"

int main (int argc, const char * argv[])
{
    sayHello();
    return 0;
}

building this stuff on osx works fine and runs as expected. But when compiling/linking it on ubuntu (using GNUStep) results in an segmentation fault when executing the binary. I nailed it down to the casting operation in the printf statement, but I have no clue what I'm doing wrong here or how I can solve this.

Interesting note: This works fine when using gcc toolchain to build the executable. I just see this issue when building it with clang on ubuntu.

Any help is very much appreciated.

回答1:

To fix this issue, I ended up changing my code to the following:

...
void sayHello()
{
    #ifdef FRENCH
    NSString *helloWorld = @"${HELLO_WORLD_FRENCH}\\n";
    #else
    NSString *helloWorld = @"${HELLO_WORLD}\\n";
    #endif

    NSFileHandle *stdout = [NSFileHandle fileHandleWithStandardOutput];
    NSData *strData = [helloWorld dataUsingEncoding: NSASCIIStringEncoding];
    [stdout writeData: strData];
}
...

来源：https://stackoverflow.com/questions/21242527/segmentation-fault-when-attemping-to-print-nsstring-as-utf8string