1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
#include<assert.h> #include<stdio.h> int main (int argc, char *argv[]) { FILE *fp; int res; long len; fp = fopen("testappend", "wb+"); res = fwrite("1234567890", 10, 1, fp); fclose(fp); fp = fopen("testappend", "ab+"); res = fwrite("1234567890", 10, 1, fp); fseek(fp, -7, SEEK_END); len = ftell(fp); assert(len == 13); fclose(fp); puts("success"); return 0; }