/*
* Copyright (C) 2012 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <gtest/gtest.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <math.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <wchar.h>
#include <locale.h>
#include "TemporaryFile.h"
TEST(stdio, tmpfile_fileno_fprintf_rewind_fgets) {
FILE* fp = tmpfile();
ASSERT_TRUE(fp != NULL);
int fd = fileno(fp);
ASSERT_NE(fd, -1);
struct stat sb;
int rc = fstat(fd, &sb);
ASSERT_NE(rc, -1);
ASSERT_EQ(sb.st_mode & 0777, 0600U);
rc = fprintf(fp, "hello\n");
ASSERT_EQ(rc, 6);
rewind(fp);
char buf[16];
char* s = fgets(buf, sizeof(buf), fp);
ASSERT_TRUE(s != NULL);
ASSERT_STREQ("hello\n", s);
fclose(fp);
}
TEST(stdio, dprintf) {
TemporaryFile tf;
int rc = dprintf(tf.fd, "hello\n");
ASSERT_EQ(rc, 6);
lseek(tf.fd, SEEK_SET, 0);
FILE* tfile = fdopen(tf.fd, "r");
ASSERT_TRUE(tfile != NULL);
char buf[7];
ASSERT_EQ(buf, fgets(buf, sizeof(buf), tfile));
ASSERT_STREQ("hello\n", buf);
// Make sure there isn't anything else in the file.
ASSERT_EQ(NULL, fgets(buf, sizeof(buf), tfile));
fclose(tfile);
}
TEST(stdio, getdelim) {
FILE* fp = tmpfile();
ASSERT_TRUE(fp != NULL);
const char* line_written = "This is a test";
int rc = fprintf(fp, "%s", line_written);
ASSERT_EQ(rc, static_cast<int>(strlen(line_written)));
rewind(fp);
char* word_read = NULL;
size_t allocated_length = 0;
const char* expected[] = { "This ", " ", "is ", "a ", "test" };
for (size_t i = 0; i < 5; ++i) {
ASSERT_FALSE(feof(fp));
ASSERT_EQ(getdelim(&word_read, &allocated_length, ' ', fp), static_cast<int>(strlen(expected[i])));
ASSERT_GE(allocated_length, strlen(expected[i]));
ASSERT_STREQ(word_read, expected[i]);
}
// The last read should have set the end-of-file indicator for the stream.
ASSERT_TRUE(feof(fp));
clearerr(fp);
// getdelim returns -1 but doesn't set errno if we're already at EOF.
// It should set the end-of-file indicator for the stream, though.
errno = 0;
ASSERT_EQ(getdelim(&word_read, &allocated_length, ' ', fp), -1);
ASSERT_EQ(0, errno);
ASSERT_TRUE(feof(fp));
free(word_read);
fclose(fp);
}
TEST(stdio, getdelim_invalid) {
FILE* fp = tmpfile();
ASSERT_TRUE(fp != NULL);
char* buffer = NULL;
size_t buffer_length = 0;
// The first argument can't be NULL.
errno = 0;
ASSERT_EQ(getdelim(NULL, &buffer_length, ' ', fp), -1);
ASSERT_EQ(EINVAL, errno);
// The second argument can't be NULL.
errno = 0;
ASSERT_EQ(getdelim(&buffer, NULL, ' ', fp), -1);
ASSERT_EQ(EINVAL, errno);
// The underlying fd can't be closed.
ASSERT_EQ(0, close(fileno(fp)));
errno = 0;
ASSERT_EQ(getdelim(&buffer, &buffer_length, ' ', fp), -1);
ASSERT_EQ(EBADF, errno);
fclose(fp);
}
TEST(stdio, getline) {
FILE* fp = tmpfile();
ASSERT_TRUE(fp != NULL);
const char* line_written = "This is a test for getline\n";
const size_t line_count = 5;
for (size_t i = 0; i < line_count; ++i) {
int rc = fprintf(fp, "%s", line_written);
ASSERT_EQ(rc, static_cast<int>(strlen(line_written)));
}
rewind(fp);
char* line_read = NULL;
size_t allocated_length = 0;
size_t read_line_count = 0;
ssize_t read_char_count;
while ((read_char_count = getline(&line_read, &allocated_length, fp)) != -1) {
ASSERT_EQ(read_char_count, static_cast<int>(strlen(line_written)));
ASSERT_GE(allocated_length, strlen(line_written));
ASSERT_STREQ(line_read, line_written);
++read_line_count;
}
ASSERT_EQ(read_line_count, line_count);
// The last read should have set the end-of-file indicator for the stream.
ASSERT_TRUE(feof(fp));
clearerr(fp);
// getline returns -1 but doesn't set errno if we're already at EOF.
// It should set the end-of-file indicator for the stream, though.
errno = 0;
ASSERT_EQ(getline(&line_read, &allocated_length, fp), -1);
ASSERT_EQ(0, errno);
ASSERT_TRUE(feof(fp));
free(line_read);
fclose(fp);
}
TEST(stdio, getline_invalid) {
FILE* fp = tmpfile();
ASSERT_TRUE(fp != NULL);
char* buffer = NULL;
size_t buffer_length = 0;
// The first argument can't be NULL.
errno = 0;
ASSERT_EQ(getline(NULL, &buffer_length, fp), -1);
ASSERT_EQ(EINVAL, errno);
// The second argument can't be NULL.
errno = 0;
ASSERT_EQ(getline(&buffer, NULL, fp), -1);
ASSERT_EQ(EINVAL, errno);
// The underlying fd can't be closed.
ASSERT_EQ(0, close(fileno(fp)));
errno = 0;
ASSERT_EQ(getline(&buffer, &buffer_length, fp), -1);
ASSERT_EQ(EBADF, errno);
fclose(fp);
}
TEST(stdio, printf_ssize_t) {
// http://b/8253769
ASSERT_EQ(sizeof(ssize_t), sizeof(long int));
ASSERT_EQ(sizeof(ssize_t), sizeof(size_t));
// For our 32-bit ABI, we had a ssize_t definition that confuses GCC into saying:
// error: format '%zd' expects argument of type 'signed size_t',
// but argument 4 has type 'ssize_t {aka long int}' [-Werror=format]
ssize_t v = 1;
char buf[32];
snprintf(buf, sizeof(buf), "%zd", v);
}
// https://code.google.com/p/android/issues/detail?id=64886
TEST(stdio, snprintf_a) {
char buf[BUFSIZ];
EXPECT_EQ(23, snprintf(buf, sizeof(buf), "<%a>", 9990.235));
EXPECT_STREQ("<0x1.3831e147ae148p+13>", buf);
}
TEST(stdio, snprintf_lc) {
char buf[BUFSIZ];
wint_t wc = L'a';
EXPECT_EQ(3, snprintf(buf, sizeof(buf), "<%lc>", wc));
EXPECT_STREQ("<a>", buf);
}
TEST(stdio, snprintf_ls) {
char buf[BUFSIZ];
wchar_t* ws = NULL;
EXPECT_EQ(8, snprintf(buf, sizeof(buf), "<%ls>", ws));
EXPECT_STREQ("<(null)>", buf);
wchar_t chars[] = { L'h', L'i', 0 };
ws = chars;
EXPECT_EQ(4, snprintf(buf, sizeof(buf), "<%ls>", ws));
EXPECT_STREQ("<hi>", buf);
}
TEST(stdio, snprintf_n) {
#if defined(__BIONIC__)
// http://b/14492135
char buf[32];
int i = 1234;
EXPECT_EQ(5, snprintf(buf, sizeof(buf), "a %n b", &i));
EXPECT_EQ(1234, i);
EXPECT_STREQ("a n b", buf);
#else
GTEST_LOG_(INFO) << "This test does nothing.\n";
#endif
}
TEST(stdio, snprintf_smoke) {
char buf[BUFSIZ];
snprintf(buf, sizeof(buf), "a");
EXPECT_STREQ("a", buf);
snprintf(buf, sizeof(buf), "%%");
EXPECT_STREQ("%", buf);
snprintf(buf, sizeof(buf), "01234");
EXPECT_STREQ("01234", buf);
snprintf(buf, sizeof(buf), "a%sb", "01234");
EXPECT_STREQ("a01234b", buf);
char* s = NULL;
snprintf(buf, sizeof(buf), "a%sb", s);
EXPECT_STREQ("a(null)b", buf);
snprintf(buf, sizeof(buf), "aa%scc", "bb");
EXPECT_STREQ("aabbcc", buf);
snprintf(buf, sizeof(buf), "a%cc", 'b');
EXPECT_STREQ("abc", buf);
snprintf(buf, sizeof(buf), "a%db", 1234);
EXPECT_STREQ("a1234b", buf);
snprintf(buf, sizeof(buf), "a%db", -8123);
EXPECT_STREQ("a-8123b", buf);
snprintf(buf, sizeof(buf), "a%hdb", static_cast<short>(0x7fff0010));
EXPECT_STREQ("a16b", buf);
snprintf(buf, sizeof(buf), "a%hhdb", static_cast<char>(0x7fffff10));
EXPECT_STREQ("a16b", buf);
snprintf(buf, sizeof(buf), "a%lldb", 0x1000000000LL);
EXPECT_STREQ("a68719476736b", buf);
snprintf(buf, sizeof(buf), "a%ldb", 70000L);
EXPECT_STREQ("a70000b", buf);
snprintf(buf, sizeof(buf), "a%pb", reinterpret_cast<void*>(0xb0001234));
EXPECT_STREQ("a0xb0001234b", buf);
snprintf(buf, sizeof(buf), "a%xz", 0x12ab);
EXPECT_STREQ("a12abz", buf);
snprintf(buf, sizeof(buf), "a%Xz", 0x12ab);
EXPECT_STREQ("a12ABz", buf);
snprintf(buf, sizeof(buf), "a%08xz", 0x123456);
EXPECT_STREQ("a00123456z", buf);
snprintf(buf, sizeof(buf), "a%5dz", 1234);
EXPECT_STREQ("a 1234z", buf);
snprintf(buf, sizeof(buf), "a%05dz", 1234);
EXPECT_STREQ("a01234z", buf);
snprintf(buf, sizeof(buf), "a%8dz", 1234);
EXPECT_STREQ("a 1234z", buf);
snprintf(buf, sizeof(buf), "a%-8dz", 1234);
EXPECT_STREQ("a1234 z", buf);
snprintf(buf, sizeof(buf), "A%-11sZ", "abcdef");
EXPECT_STREQ("Aabcdef Z", buf);
snprintf(buf, sizeof(buf), "A%s:%dZ", "hello", 1234);
EXPECT_STREQ("Ahello:1234Z", buf);
snprintf(buf, sizeof(buf), "a%03d:%d:%02dz", 5, 5, 5);
EXPECT_STREQ("a005:5:05z", buf);
void* p = NULL;
snprintf(buf, sizeof(buf), "a%d,%pz", 5, p);
#if defined(__BIONIC__)
EXPECT_STREQ("a5,0x0z", buf);
#else // __BIONIC__
EXPECT_STREQ("a5,(nil)z", buf);
#endif // __BIONIC__
snprintf(buf, sizeof(buf), "a%lld,%d,%d,%dz", 0x1000000000LL, 6, 7, 8);
EXPECT_STREQ("a68719476736,6,7,8z", buf);
snprintf(buf, sizeof(buf), "a_%f_b", 1.23f);
EXPECT_STREQ("a_1.230000_b", buf);
snprintf(buf, sizeof(buf), "a_%g_b", 3.14);
EXPECT_STREQ("a_3.14_b", buf);
snprintf(buf, sizeof(buf), "%1$s %1$s", "print_me_twice");
EXPECT_STREQ("print_me_twice print_me_twice", buf);
}
TEST(stdio, snprintf_f_special) {
char buf[BUFSIZ];
snprintf(buf, sizeof(buf), "%f", nanf(""));
EXPECT_STRCASEEQ("NaN", buf);
snprintf(buf, sizeof(buf), "%f", HUGE_VALF);
EXPECT_STRCASEEQ("Inf", buf);
}
TEST(stdio, snprintf_g_special) {
char buf[BUFSIZ];
snprintf(buf, sizeof(buf), "%g", nan(""));
EXPECT_STRCASEEQ("NaN", buf);
snprintf(buf, sizeof(buf), "%g", HUGE_VAL);
EXPECT_STRCASEEQ("Inf", buf);
}
TEST(stdio, snprintf_d_INT_MAX) {
char buf[BUFSIZ];
snprintf(buf, sizeof(buf), "%d", INT_MAX);
EXPECT_STREQ("2147483647", buf);
}
TEST(stdio, snprintf_d_INT_MIN) {
char buf[BUFSIZ];
snprintf(buf, sizeof(buf), "%d", INT_MIN);
EXPECT_STREQ("-2147483648", buf);
}
TEST(stdio, snprintf_ld_LONG_MAX) {
char buf[BUFSIZ];
snprintf(buf, sizeof(buf), "%ld", LONG_MAX);
#if __LP64__
EXPECT_STREQ("9223372036854775807", buf);
#else
EXPECT_STREQ("2147483647", buf);
#endif
}
TEST(stdio, snprintf_ld_LONG_MIN) {
char buf[BUFSIZ];
snprintf(buf, sizeof(buf), "%ld", LONG_MIN);
#if __LP64__
EXPECT_STREQ("-9223372036854775808", buf);
#else
EXPECT_STREQ("-2147483648", buf);
#endif
}
TEST(stdio, snprintf_lld_LLONG_MAX) {
char buf[BUFSIZ];
snprintf(buf, sizeof(buf), "%lld", LLONG_MAX);
EXPECT_STREQ("9223372036854775807", buf);
}
TEST(stdio, snprintf_lld_LLONG_MIN) {
char buf[BUFSIZ];
snprintf(buf, sizeof(buf), "%lld", LLONG_MIN);
EXPECT_STREQ("-9223372036854775808", buf);
}
TEST(stdio, snprintf_e) {
char buf[BUFSIZ];
snprintf(buf, sizeof(buf), "%e", 1.5);
EXPECT_STREQ("1.500000e+00", buf);
snprintf(buf, sizeof(buf), "%Le", 1.5l);
EXPECT_STREQ("1.500000e+00", buf);
}
TEST(stdio, snprintf_negative_zero_5084292) {
char buf[BUFSIZ];
snprintf(buf, sizeof(buf), "%f", -0.0);
EXPECT_STREQ("-0.000000", buf);
}
TEST(stdio, snprintf_utf8_15439554) {
locale_t cloc = newlocale(LC_ALL, "C.UTF-8", 0);
locale_t old_locale = uselocale(cloc);
// http://b/15439554
char buf[BUFSIZ];
// 1-byte character.
snprintf(buf, sizeof(buf), "%dx%d", 1, 2);
EXPECT_STREQ("1x2", buf);
// 2-byte character.
snprintf(buf, sizeof(buf), "%d\xc2\xa2%d", 1, 2);
EXPECT_STREQ("1¢2", buf);
// 3-byte character.
snprintf(buf, sizeof(buf), "%d\xe2\x82\xac%d", 1, 2);
EXPECT_STREQ("1€2", buf);
// 4-byte character.
snprintf(buf, sizeof(buf), "%d\xf0\xa4\xad\xa2%d", 1, 2);
EXPECT_STREQ("1𤭢2", buf);
uselocale(old_locale);
freelocale(cloc);
}
TEST(stdio, fprintf_failures_7229520) {
// http://b/7229520
FILE* fp;
// Unbuffered case where the fprintf(3) itself fails.
ASSERT_NE(nullptr, fp = tmpfile());
setbuf(fp, NULL);
ASSERT_EQ(4, fprintf(fp, "epic"));
ASSERT_EQ(0, close(fileno(fp)));
ASSERT_EQ(-1, fprintf(fp, "fail"));
ASSERT_EQ(-1, fclose(fp));
// Buffered case where we won't notice until the fclose(3).
// It's likely this is what was actually seen in http://b/7229520,
// and that expecting fprintf to fail is setting yourself up for
// disappointment. Remember to check fclose(3)'s return value, kids!
ASSERT_NE(nullptr, fp = tmpfile());
ASSERT_EQ(4, fprintf(fp, "epic"));
ASSERT_EQ(0, close(fileno(fp)));
ASSERT_EQ(4, fprintf(fp, "fail"));
ASSERT_EQ(-1, fclose(fp));
}
TEST(stdio, popen) {
FILE* fp = popen("cat /proc/version", "r");
ASSERT_TRUE(fp != NULL);
char buf[16];
char* s = fgets(buf, sizeof(buf), fp);
buf[13] = '\0';
ASSERT_STREQ("Linux version", s);
ASSERT_EQ(0, pclose(fp));
}
TEST(stdio, getc) {
FILE* fp = fopen("/proc/version", "r");
ASSERT_TRUE(fp != NULL);
ASSERT_EQ('L', getc(fp));
ASSERT_EQ('i', getc(fp));
ASSERT_EQ('n', getc(fp));
ASSERT_EQ('u', getc(fp));
ASSERT_EQ('x', getc(fp));
fclose(fp);
}
TEST(stdio, putc) {
FILE* fp = fopen("/proc/version", "r");
ASSERT_TRUE(fp != NULL);
ASSERT_EQ(EOF, putc('x', fp));
fclose(fp);
}
TEST(stdio, sscanf) {
char s1[123];
int i1;
double d1;
char s2[123];
ASSERT_EQ(3, sscanf(" hello 123 1.23 ", "%s %i %lf %s", s1, &i1, &d1, s2));
ASSERT_STREQ("hello", s1);
ASSERT_EQ(123, i1);
ASSERT_DOUBLE_EQ(1.23, d1);
}
TEST(stdio, cantwrite_EBADF) {
// If we open a file read-only...
FILE* fp = fopen("/proc/version", "r");
// ...all attempts to write to that file should return failure.
// They should also set errno to EBADF. This isn't POSIX, but it's traditional.
// glibc gets the wide-character functions wrong.
errno = 0;
EXPECT_EQ(EOF, putc('x', fp));
EXPECT_EQ(EBADF, errno);
errno = 0;
EXPECT_EQ(EOF, fprintf(fp, "hello"));
EXPECT_EQ(EBADF, errno);
errno = 0;
EXPECT_EQ(EOF, fwprintf(fp, L"hello"));
#if defined(__BIONIC__)
EXPECT_EQ(EBADF, errno);
#endif
errno = 0;
EXPECT_EQ(0U, fwrite("hello", 1, 2, fp));
EXPECT_EQ(EBADF, errno);
errno = 0;
EXPECT_EQ(EOF, fputs("hello", fp));
EXPECT_EQ(EBADF, errno);
errno = 0;
EXPECT_EQ(WEOF, fputwc(L'x', fp));
#if defined(__BIONIC__)
EXPECT_EQ(EBADF, errno);
#endif
}
// Tests that we can only have a consistent and correct fpos_t when using
// f*pos functions (i.e. fpos doesn't get inside a multi byte character).
TEST(stdio, consistent_fpos_t) {
ASSERT_STREQ("C.UTF-8", setlocale(LC_CTYPE, "C.UTF-8"));
uselocale(LC_GLOBAL_LOCALE);
FILE* fp = tmpfile();
ASSERT_TRUE(fp != NULL);
wchar_t mb_one_bytes = L'h';
wchar_t mb_two_bytes = 0x00a2;
wchar_t mb_three_bytes = 0x20ac;
wchar_t mb_four_bytes = 0x24b62;
// Write to file.
ASSERT_EQ(mb_one_bytes, static_cast<wchar_t>(fputwc(mb_one_bytes, fp)));
ASSERT_EQ(mb_two_bytes, static_cast<wchar_t>(fputwc(mb_two_bytes, fp)));
ASSERT_EQ(mb_three_bytes, static_cast<wchar_t>(fputwc(mb_three_bytes, fp)));
ASSERT_EQ(mb_four_bytes, static_cast<wchar_t>(fputwc(mb_four_bytes, fp)));
rewind(fp);
// Record each character position.
fpos_t pos1;
fpos_t pos2;
fpos_t pos3;
fpos_t pos4;
fpos_t pos5;
EXPECT_EQ(0, fgetpos(fp, &pos1));
ASSERT_EQ(mb_one_bytes, static_cast<wchar_t>(fgetwc(fp)));
EXPECT_EQ(0, fgetpos(fp, &pos2));
ASSERT_EQ(mb_two_bytes, static_cast<wchar_t>(fgetwc(fp)));
EXPECT_EQ(0, fgetpos(fp, &pos3));
ASSERT_EQ(mb_three_bytes, static_cast<wchar_t>(fgetwc(fp)));
EXPECT_EQ(0, fgetpos(fp, &pos4));
ASSERT_EQ(mb_four_bytes, static_cast<wchar_t>(fgetwc(fp)));
EXPECT_EQ(0, fgetpos(fp, &pos5));
#if defined(__BIONIC__)
// Bionic's fpos_t is just an alias for off_t. This is inherited from OpenBSD
// upstream. Glibc differs by storing the mbstate_t inside its fpos_t. In
// Bionic (and upstream OpenBSD) the mbstate_t is stored inside the FILE
// structure.
ASSERT_EQ(0, static_cast<off_t>(pos1));
ASSERT_EQ(1, static_cast<off_t>(pos2));
ASSERT_EQ(3, static_cast<off_t>(pos3));
ASSERT_EQ(6, static_cast<off_t>(pos4));
ASSERT_EQ(10, static_cast<off_t>(pos5));
#endif
// Exercise back and forth movements of the position.
ASSERT_EQ(0, fsetpos(fp, &pos2));
ASSERT_EQ(mb_two_bytes, static_cast<wchar_t>(fgetwc(fp)));
ASSERT_EQ(0, fsetpos(fp, &pos1));
ASSERT_EQ(mb_one_bytes, static_cast<wchar_t>(fgetwc(fp)));
ASSERT_EQ(0, fsetpos(fp, &pos4));
ASSERT_EQ(mb_four_bytes, static_cast<wchar_t>(fgetwc(fp)));
ASSERT_EQ(0, fsetpos(fp, &pos3));
ASSERT_EQ(mb_three_bytes, static_cast<wchar_t>(fgetwc(fp)));
ASSERT_EQ(0, fsetpos(fp, &pos5));
ASSERT_EQ(WEOF, fgetwc(fp));
fclose(fp);
}
// Exercise the interaction between fpos and seek.
TEST(stdio, fpos_t_and_seek) {
ASSERT_STREQ("C.UTF-8", setlocale(LC_CTYPE, "C.UTF-8"));
uselocale(LC_GLOBAL_LOCALE);
// In glibc-2.16 fseek doesn't work properly in wide mode
// (https://sourceware.org/bugzilla/show_bug.cgi?id=14543). One workaround is
// to close and re-open the file. We do it in order to make the test pass
// with all glibcs.
TemporaryFile tf;
FILE* fp = fdopen(tf.fd, "w+");
ASSERT_TRUE(fp != NULL);
wchar_t mb_two_bytes = 0x00a2;
wchar_t mb_three_bytes = 0x20ac;
wchar_t mb_four_bytes = 0x24b62;
// Write to file.
ASSERT_EQ(mb_two_bytes, static_cast<wchar_t>(fputwc(mb_two_bytes, fp)));
ASSERT_EQ(mb_three_bytes, static_cast<wchar_t>(fputwc(mb_three_bytes, fp)));
ASSERT_EQ(mb_four_bytes, static_cast<wchar_t>(fputwc(mb_four_bytes, fp)));
fflush(fp);
fclose(fp);
fp = fopen(tf.filename, "r");
ASSERT_TRUE(fp != NULL);
// Store a valid position.
fpos_t mb_two_bytes_pos;
ASSERT_EQ(0, fgetpos(fp, &mb_two_bytes_pos));
// Move inside mb_four_bytes with fseek.
long offset_inside_mb = 6;
ASSERT_EQ(0, fseek(fp, offset_inside_mb, SEEK_SET));
// Store the "inside multi byte" position.
fpos_t pos_inside_mb;
ASSERT_EQ(0, fgetpos(fp, &pos_inside_mb));
#if defined(__BIONIC__)
ASSERT_EQ(offset_inside_mb, static_cast<off_t>(pos_inside_mb));
#endif
// Reading from within a byte should produce an error.
ASSERT_EQ(WEOF, fgetwc(fp));
ASSERT_EQ(EILSEQ, errno);
// Reverting to a valid position should work.
ASSERT_EQ(0, fsetpos(fp, &mb_two_bytes_pos));
ASSERT_EQ(mb_two_bytes, static_cast<wchar_t>(fgetwc(fp)));
// Moving withing a multi byte with fsetpos should work but reading should
// produce an error.
ASSERT_EQ(0, fsetpos(fp, &pos_inside_mb));
ASSERT_EQ(WEOF, fgetwc(fp));
ASSERT_EQ(EILSEQ, errno);
fclose(fp);
}