Help making manipulable variable

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1

Hello, I'm a newbie in C, but i'm trying to make a file to configurate/manipulate variables of a C code.

I tried using int and extern int throught a header or another C code but it doesn't seems to work (even throught the makefile). I also tried (with XML) to put a data structure to hold the shared variables with the XML_SetUserData function to pass a pointer to this structure to the handlers.

Maybe i did something wrong, but i can't find where. Any help is welcome. Thanks.

---------- Post updated at 04:46 PM ---------- Previous update was at 03:41 PM ----------

So,here is code.h

#ifndef _CODE_H
#define _CODE_H
#include <stdio.h>
#include <stdlib.h>

#define X 1
typedef unsigned char X_Bool;
#define X_TRUE ((X_Bool) 1)
#define X_FALSE ((X_Bool) 0)
#define X_MODE ((X_Bool) 2)
#endif

then conf.c

int M;
M = 2;

and then code.c

#include <stdio.h>
#include "code.h"
extern int X;
extern int M;
int main(int argc, char *argv[]) {
while (1) {
printf("\n%s\n", M);
printf("\n%s\n", X);
printf("\n%s\n", X_MODE);
}

and then the compile

gcc code.c conf.c -o decode `pkg-config --cflags --libs gstreamer-0.10

I want to change variable throught code.h or conf.c for code.c but it fail. It seems to ignore it with no errors.

2

The code you've given won't compile, missing brackets in places.

I don't know what your while-loop is for. That will just print the same things over and over.

The variable X won't work right, because X also exists as a #define, whenever you use X it will be turned into 1 by simple text replacement.

The variable M ought to properly show up as 2. What were you expecting it to do, and in what way was it not working?

3

I'm using Gstreamer, and i want to have the possibility to change parameters in my pipeline throught a configuration file.

Here is my pipeline:

str = g_strdup_printf (
   "rtspsrc protocols=PTCP latency=LAT "
   " timeout=TIMO  buffer-mode=BUFM location=%s name=src"
   " ! queue ! gstrtpbin latency=LATE name=srcbin "
   " ! queue min-threshold-time=QUE ! rtph264depay ! ffdec_h264"
   " ! interlace top-field-first=true field-pattern=FP"
   " ! videoscale add-borders=true ! videorate"
   " ! colorspace"
   " ! video/x-raw-yuv,framerate=25/1,height=576,width=720,format=(fourcc)UYVY"
   " ! decklinksink name=sink mode= mood "
   " src. ! queue min-threshold-time=QMTT ! rtpmp4adepay !  aacparse ! faad ! audioconvert ! audioresample ! sink. sync=true"
   ,argv[1]);
pipeline = gst_parse_launch (str,NULL);

which i want to be able change PTCP, LAT, TIMO, BUFM, LATE, QUE, FP, mood, and the caps

4

An .h file is not a configuration file. It gets read when you run gcc, not when you run the program.

You could have a simple configuration file like this:

VAR1=VALUE1
VAR2=VALUE2
...

and use it like this:

char buf[512], var[512], val[512];
FILE *fp=fopen("/path/to/configfile", "r");

setenv("protocols", "PCTP"); // Set a default

while(fgets(buf, 512, fp) != NULL)
{
        if(sscanf(buf, "%[^=]=%s", var, val) != 2) continue;
        setenv(var, val);
}
fclose(fp);

str = g_strdup_printf (
   "rtspsrc protocols=%s latency=LAT "
   " timeout=TIMO  buffer-mode=BUFM location=%s name=src"
   " ! queue ! gstrtpbin latency=LATE name=srcbin "
   " ! queue min-threshold-time=QUE ! rtph264depay ! ffdec_h264"
   " ! interlace top-field-first=true field-pattern=FP"
   " ! videoscale add-borders=true ! videorate"
   " ! colorspace"
   " ! video/x-raw-yuv,framerate=25/1,height=576,width=720,format=(fourcc)UYVY"
   " ! decklinksink name=sink mode= mood "
   " src. ! queue min-threshold-time=QMTT ! rtpmp4adepay !  aacparse ! faad ! audioconvert ! audioresample ! sink. sync=true"
   ,getenv("protocols"), argv[1]);
5

Thank you Corona ! I've got things to do, but i'll do it as soon as possible.

I have now done the code, and it work. Thanks again :slight_smile: