file.c


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#include <errno.h>
#include <string.h>

#include "file.h"
#include "print.h"

long
file_size(FILE * const file)
{
    fpos_t p;
    
    if ((fgetpos(file, &p) != 0)
	|| (fseek(file, 0L, SEEK_END) != 0)) {
	return -1;
    }
    
    const long size = ftell(file);
    
    if (fsetpos(file, &p) != 0) {
	return -1;
    }
    
    return size;
}