Get GNU GMP test suite fully passing

- Fix stdio fmemopen() buffer behaviors
- Fix scanf() to return EOF when appropriate
- Prefer fseek/ftell names over fseeko/ftello
- Ensure locale field is always set in the TIB
- Fix recent regression in vfprintf() return count
- Make %n directive in scanf() have standard behavior

test/libc/stdio/fgetln_test.c

@@ -18,6 +18,7 @@
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/calls/calls.h"
 #include "libc/mem/gc.h"
+#include "libc/mem/gc.internal.h"
 #include "libc/mem/mem.h"
 #include "libc/stdio/stdio.h"
 #include "libc/str/str.h"
@@ -28,7 +29,7 @@
 
 TEST(fgetln, test) {
   FILE *f;
-  f = fmemopen(_gc(strdup(kHyperion)), kHyperionSize, "r+");
+  f = fmemopen(gc(strdup(kHyperion)), kHyperionSize, "r+");
   EXPECT_STREQ("The fall of Hyperion - a Dream\n", fgetln(f, 0));
   EXPECT_STREQ("John Keats\n", fgetln(f, 0));
   EXPECT_STREQ("\n", fgetln(f, 0));
@@ -81,7 +82,7 @@ TEST(fgetln, testReadingFromStdin_doesntLeakMemory) {
 }
 
 BENCH(fgetln, bench) {
-  FILE *f = fmemopen(_gc(strdup(kHyperion)), kHyperionSize, "r+");
+  FILE *f = fmemopen(gc(strdup(kHyperion)), kHyperionSize, "r+");
   EZBENCH2("fgetln", donothing, fgetln(f, 0));
   EZBENCH2("xgetline", donothing, free(xgetline(f)));
   fclose(f);

test/libc/stdio/fmemopen_test.c

@@ -16,7 +16,12 @@
 │ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/calls/calls.h"
+#include "libc/errno.h"
+#include "libc/mem/gc.internal.h"
+#include "libc/mem/mem.h"
 #include "libc/stdio/stdio.h"
+#include "libc/stdio/temp.h"
 #include "libc/testlib/testlib.h"
 
 TEST(fmemopen, testWriteRewindRead) {
@@ -30,10 +35,43 @@ TEST(fmemopen, testWriteRewindRead) {
   fclose(f);
 }
 
-/* TEST(fmemopen, testWriteRead_readsNothingButNotEof) { */
-/*   char c; */
-/*   FILE *f; */
-/*   f = fmemopen(NULL, BUFSIZ, "w+"); */
-/*   EXPECT_EQ(1, fwrite("c", 1, 1, f)); */
-/*   EXPECT_EQ(0, fread(&c, 1, 1, f)); */
-/* } */
+TEST(fmemopen_fprintf, test) {
+  FILE *f = fmemopen(NULL, BUFSIZ, "w+");
+  EXPECT_EQ(1, fprintf(f, "%ld", 0L));
+  rewind(f);
+  char buf[8] = {0};
+  EXPECT_EQ(1, fread(&buf, 1, 8, f));
+  EXPECT_STREQ("0", buf);
+  fclose(f);
+}
+
+TEST(fmemopen, seekEofRead) {
+  FILE *f = fmemopen("x", 1, "r+");
+  ASSERT_SYS(EINVAL, -1, fseek(f, -1, SEEK_SET));
+  ASSERT_SYS(EINVAL, -1, fseek(f, +1, SEEK_END));
+  ASSERT_EQ(0, fseek(f, 0, SEEK_END));
+  ASSERT_FALSE(feof(f));
+  ASSERT_EQ(-1, fgetc(f));
+  ASSERT_TRUE(feof(f));
+  fclose(f);
+}
+
+TEST(tmpfile_fprintf, test) {
+  FILE *f = tmpfile();
+  EXPECT_EQ(1, fprintf(f, "%ld", 0L));
+  rewind(f);
+  char buf[8] = {0};
+  EXPECT_EQ(1, fread(&buf, 1, 8, f));
+  EXPECT_STREQ("0", buf);
+  fclose(f);
+}
+
+TEST(fmemopen, small) {
+  FILE *f = fmemopen(gc(malloc(1)), 1, "w+");
+  EXPECT_EQ(3, fprintf(f, "%ld", 123L));
+  rewind(f);
+  char buf[8] = {0};
+  EXPECT_EQ(1, fread(&buf, 1, 8, f));
+  EXPECT_STREQ("1", buf);
+  fclose(f);
+}

test/libc/stdio/ftell_test.c

@@ -17,8 +17,8 @@
 │ PERFORMANCE OF THIS SOFTWARE.                                                │
 ╚─────────────────────────────────────────────────────────────────────────────*/
 #include "libc/calls/calls.h"
-#include "libc/mem/mem.h"
 #include "libc/mem/gc.internal.h"
+#include "libc/mem/mem.h"
 #include "libc/stdio/stdio.h"
 #include "libc/testlib/testlib.h"
 #include "libc/x/x.h"

test/libc/stdio/sscanf_test.c

@@ -42,7 +42,6 @@ TEST(sscanf, testMultiple) {
 
 TEST(sscanf, testDecimal) {
   EXPECT_EQ(123, sscanf1("123", "%d"));
-  EXPECT_EQ(123, sscanf1("123", "%n"));
   EXPECT_EQ(123, sscanf1("123", "%u"));
   EXPECT_EQ((uint32_t)-123, sscanf1("-123", "%d"));
 }
@@ -258,3 +257,30 @@ TEST(sscanf, test0) {
   ASSERT_EQ(sscanf("0", "%b", &v), 1);
   ASSERT_EQ(v, 0);
 }
+
+TEST(sscanf, n) {
+  int x, y;
+  EXPECT_EQ(1, sscanf("7 2 3 4", "%d%n", &x, &y));
+  EXPECT_EQ(7, x);
+  EXPECT_EQ(1, y);
+}
+
+TEST(sscanf, eofForNoMatching) {
+  int y = 666;
+  char x[8] = "hi";
+  EXPECT_EQ(-1, sscanf("   ", "%s%n", &x, &y));
+  EXPECT_STREQ("hi", x);
+  EXPECT_EQ(666, y);
+}
+
+TEST(sscanf, eofConditions) {
+  int x = 666;
+  EXPECT_EQ(-1, sscanf("", "%d", &x));
+  EXPECT_EQ(666, x);
+  EXPECT_EQ(-1, sscanf(" ", "%d", &x));
+  EXPECT_EQ(666, x);
+  EXPECT_EQ(-1, sscanf("123", "%*d%d", &x));
+  EXPECT_EQ(666, x);
+  EXPECT_EQ(-1, sscanf("123", "%*d%n", &x));
+  EXPECT_EQ(666, x);
+}