#include <stdio.h> #include <stdlib.h> #include <string.h> #include <sys/types.h> #include <sys/stat.h> #include <fcntl.h> #include <unistd.h> #include <assert.h> #define ARRAY_SIZE(arr) (sizeof(arr)/sizeof(*arr)) int main(void) { struct { off_t offset; int whence; } tests[] = { { 0x00, SEEK_SET }, { 0x01, SEEK_SET }, { 0xFF, SEEK_SET } }; char buf[2000]; off_t ret; int i, fd; FILE *fp; int tmp; fd = open("lseek.out", O_RDWR|O_CREAT, 0600); if (fd == -1) { perror("open(lseek.out) failed"); return 1; } unlink("lseek.out"); fp = fdopen(fd, "rw"); if (fp == NULL) { perror("fopen(lseek.out) failed"); return 1; } memset(buf, 0xAB, sizeof(buf)); ret = write(fd, buf, sizeof(buf)); if (ret != sizeof(buf)) { fprintf(stderr, "write() failed to write %zi bytes (wrote %li): ", sizeof(buf), (long)ret); perror(""); return 1; } tmp = fseeko(fp, 1024, SEEK_SET); assert(tmp == 0); tmp = fseeko(fp, (off_t)-16, SEEK_CUR); assert(tmp == 0); ret = ftell(fp); if (ret != (1024-16)) { fprintf(stderr, "ftell() failed, we wanted pos %i but got %li: ", (1024-16), (long)ret); perror(""); return 1; } for (i = 0; i < ARRAY_SIZE(tests); ++i) { ret = lseek(fd, tests[i].offset, tests[i].whence); if (ret != tests[i].offset) { fprintf(stderr, "lseek(%li,%i) failed (wanted %li, got %li): ", (long)tests[i].offset, tests[i].whence, (long)tests[i].offset, (long)ret); perror(""); return 1; } ret = fseek(fp, tests[i].offset, tests[i].whence); if (ret != 0) { fprintf(stderr, "fseek(%li,%i) failed (wanted 0, got %li): ", (long)tests[i].offset, tests[i].whence, (long)ret); perror(""); return 1; } } fclose(fp); close(fd); printf("Success!\n"); return 0; }