libc/src/stdio/scanf.cpp

   1 //===-- Implementation of scanf ---------------------------------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "src/stdio/scanf.h"
  10
  11 #include "src/__support/File/file.h"
  12 #include "src/__support/arg_list.h"
  13 #include "src/stdio/scanf_core/vfscanf_internal.h"
  14
  15 #include <stdarg.h>
  16 #include <stdio.h>
  17
  18 #ifndef LIBC_COPT_STDIO_USE_SYSTEM_FILE
  19 #define SCANF_STDIN LIBC_NAMESPACE::stdin
  20 #else // LIBC_COPT_STDIO_USE_SYSTEM_FILE
  21 #define SCANF_STDIN ::stdin
  22 #endif // LIBC_COPT_STDIO_USE_SYSTEM_FILE
  23
  24 namespace LIBC_NAMESPACE {
  25
  26 LLVM_LIBC_FUNCTION(int, scanf, (const char *__restrict format, ...)) {
  27   va_list vlist;
  28   va_start(vlist, format);
  29   internal::ArgList args(vlist); // This holder class allows for easier copying
  30                                  // and pointer semantics, as well as handling
  31                                  // destruction automatically.
  32   va_end(vlist);
  33   int ret_val = scanf_core::vfscanf_internal(
  34       reinterpret_cast<::FILE *>(SCANF_STDIN), format, args);
  35   // This is done to avoid including stdio.h in the internals. On most systems
  36   // EOF is -1, so this will be transformed into just "return ret_val".
  37   return (ret_val == -1) ? EOF : ret_val;
  38 }
  39
  40 } // namespace LIBC_NAMESPACE