Hello,
found the following curious behaviour, If I try to run from within xcode (pressing Run) the following code:
#include <unistd.h>
int main(int argc, const char * argv[])
{
char *args[] = {"/bin/ls", "-r", "-t", "-l", (char *) 0 };
execv(args[0], args);
return 0;
}
the program does not print the expected list of files and folders but instead exits with:
Message from debugger: Terminated due to signal 5
Program ended with exit code: 5
But if I try to run the exact same compiled program from the terminal, it works as expected. I lost so many hours wondering what I was doing wrong, but apparently it was the xcode console that does not play nice with execing? Could it be that changing the process image throws a wrench into xcode? Anybody has any idea why this could be? Thanks.
Oh, you’re doing an exec* without a fork. That, and its reverse, presents unique challenges on macOS.
If you run your test and then look in Console you’ll see that ls generated a crash report:
Exception Type: EXC_CRASH (SIGTRAP)
However, this doesn’t really tell you what’s gone wrong. My best guess si that this is related to the debugger. ls is a platform binary, and thus can’t be debugged:
% lldb /bin/ls
(lldb) target create "/bin/ls"
Current executable set to '/bin/ls' (x86_64).
(lldb) r
error: process exited with status -1 …
You’re trying to get to the same destination via a different route, and the system is blocking that as well.
Share and Enjoy
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Quinn “The Eskimo!” @ Developer Technical Support @ Apple
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