• Uncategorized

About c : How-to-get-current-process-name-in-linux

Question Detail

How can I get the process name in C? The same name, which is in /proc/$pid/status. I do not want to parse that file. Is there any programmatic way of doing this?

Question Answer

If you’re on using a glibc, then:

#define _GNU_SOURCE
#include <errno.h>

extern char *program_invocation_name;
extern char *program_invocation_short_name;

See program_invocation_name(3)

Under most Unices, __progname is also defined by the libc.
The sole portable way is to use argv[0]

It’s either pointed to by the argv[0] or indeed you can read /proc/self/status. Or you can use getenv("_"), not sure who sets that and how reliable it is.

You can use __progname. However it is not better than argv[0] as it may have portability issues. But as you do not have access to argv[0] it can work as follows:-

extern char *__progname;
printf("\n%s", __progname);

I often make use of following call,

char* currentprocname = getprogname();

Look at the value of argv[0] which was passed to main. This should be the name under which your process was invoked.

This is a version that works on macOS, FreeBSD and Linux.

#if defined(__APPLE__) || defined(__FreeBSD__)
const char * appname = getprogname();
#elif defined(_GNU_SOURCE)
const char * appname = program_invocation_name;
#else
const char * appname = "?";
#endif

If you cannot access argv[] in main(), because you are implementing a library, you can have a look at my answer on a similar question here.

It basically boils down into giving you access to argc, argv[] and envp[] outside of main().
Then you could, as others have already correctly suggested, use argv[0] to retrieve the process name.

for posterity, a version that’s more C++-ish and works also on MSVC:

https://godbolt.org/z/sh3TnM

#define FMT_HEADER_ONLY
#include <fmt/format.h>

std::string get_current_process_name()
{
    #if defined(__APPLE__) || defined(__FreeBSD__)
        return getprogname();
    #elif defined(_GNU_SOURCE)
        return program_invocation_name;
    #elif defined(_WIN32)
        return __argv[0];
    #else
        return "?";
    #endif
}

int main()
{
    fmt::print("whatsmyname: {}\n", get_current_process_name());
    return 0;
}

// msvc output:
// whatsmyname: C:\Users\<user>\source\repos\Project6\Debug\Project6.exe

You may also like...

Leave a Reply

Your email address will not be published.

This site uses Akismet to reduce spam. Learn how your comment data is processed.