Question

I want to run my C code located in desktop with the header files located in other location. What should be the appropriate GCC command for compilation and execution? I have attached the code below. I am asking kind considerations and help in this regards.

#include <config.h>
#endif

#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>

#include </usr/include/pulse/simple.h>
#include </usr/include/pulse/error.h>

#define BUFSIZE 32

int main(int argc, char*argv[]) {

    /* The Sample format to use */
static const pa_sample_spec ss = {
    .format = PA_SAMPLE_S16LE,
    .rate = 44100,
    .channels = 2
};

pa_simple *s_in, *s_out = NULL;
int ret = 1;
int error;


/* Create a new playback stream */
if (!(s_out = pa_simple_new(NULL, argv[0], PA_STREAM_PLAYBACK, NULL, "playback", &ss, NULL, NULL, &error))) {
    fprintf(stderr, __FILE__": pa_simple_new() failed: %s\n", pa_strerror(error));
    goto finish;
}

  if (!(s_in = pa_simple_new(NULL, argv[0], PA_STREAM_RECORD, NULL, "record", &ss, NULL, NULL, &error))) {
    fprintf(stderr, __FILE__": pa_simple_new() failed: %s\n", pa_strerror(error));
    goto finish;
}

for (;;) {
    uint8_t buf[BUFSIZE];
    ssize_t r;

   #if 1
    pa_usec_t latency;

    if ((latency = pa_simple_get_latency(s_in, &error)) == (pa_usec_t) -1) {
        fprintf(stderr, __FILE__": pa_simple_get_latency() failed: %s\n", pa_strerror(error));
        goto finish;
    }

    fprintf(stderr, "In:  %0.0f usec    \r\n", (float)latency);

        if ((latency = pa_simple_get_latency(s_out, &error)) == (pa_usec_t) -1) {
        fprintf(stderr, __FILE__": pa_simple_get_latency() failed: %s\n",    pa_strerror(error));
            goto finish;
      }

        fprintf(stderr, "Out: %0.0f usec    \r\n", (float)latency);
#endif

        if (pa_simple_read(s_in, buf, sizeof(buf), &error) < 0) {

        fprintf(stderr, __FILE__": read() failed: %s\n", strerror(errno));
        goto finish;
    }

    /* ... and play it */
    if (pa_simple_write(s_out, buf, sizeof(buf), &error) < 0) {
        fprintf(stderr, __FILE__": pa_simple_write() failed: %s\n", pa_strerror(error));
        goto finish;
    }
}

/* Make sure that every single sample was played */
if (pa_simple_drain(s_out, &error) < 0) {
    fprintf(stderr, __FILE__": pa_simple_drain() failed: %s\n", pa_strerror(error));
    goto finish;
}

ret = 0;

finish:

if (s_in)
    pa_simple_free(s_in);
if (s_out)
    pa_simple_free(s_out);

return ret;
}

Answer 1

The C compiler includes header files (via #include) either through:

1. #include "somename.h": It starts seaching in the directory where the source is for somefile.h, if it isn’t found there it starts looking like (2)
2. #include <somename.h>: It searches a sequence of (system dependent) directories. In Unix-like systems (Linux, MacOS) this is basically /usr/include, but might add other directories.

You can control this in most compilers by -I/some/path flags, which add /some/path at the beginning of the sequence (2). Note also that the somename.h above can include /, so that if you write

#include "this/file.h"

then it looks for file.h in this directory in the current directory.