How to check if file already has data (in C)? -

i trying write simulation program in c appending file opening in append mode. file csv (comma separated values).

i write headings of simulation information before write actual values don't seem unrelated. there easy way this?

for example:

central node, system delay, bandwidth requirement  14,240,11  4,285,23  13,300,9 

my code looks this:

void data_output(file *fp){ struct stat buf; file fd = *fp; fstat(fd, &buf); fprintf(stderr,"debug------%d\n",buf.st_size); } 

the output error is:

ff.c: in function ‘data_output’: ff.c:296:2: error: incompatible type argument 1 of ‘fstat’ fstat(fd, &buf); ^ in file included /usr/include/stdio.h:29:0,              ff.c:1: /usr/include/sys/stat.h:148:5: note: expected ‘int’ argument of type ‘file’  int _exfun(fstat,( int __fd, struct stat *__sbuf ));  ^ makefile:7: recipe target 'ff.o' failed make: *** [ff.o] error 1 

what doing wrong? should typecasting in order make work?

you can check size of file. more info how size can check check post