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/__support/macros/config.h"
  14 #include "src/stdio/scanf_core/vfscanf_internal.h"
  15
  16 #include "hdr/types/FILE.h"
  17 #include <stdarg.h>
  18
  19 #ifndef LIBC_COPT_STDIO_USE_SYSTEM_FILE
  20 #define SCANF_STDIN LIBC_NAMESPACE::stdin
  21 #else // LIBC_COPT_STDIO_USE_SYSTEM_FILE
  22 #define SCANF_STDIN ::stdin
  23 #endif // LIBC_COPT_STDIO_USE_SYSTEM_FILE
  24
  25 namespace LIBC_NAMESPACE_DECL {
  26
  27 LLVM_LIBC_FUNCTION(int, scanf, (const char *__restrict format, ...)) {
  28   va_list vlist;
  29   va_start(vlist, format);
  30   internal::ArgList args(vlist); // This holder class allows for easier copying
  31                                  // and pointer semantics, as well as handling
  32                                  // destruction automatically.
  33   va_end(vlist);
  34   int ret_val = scanf_core::vfscanf_internal(
  35       reinterpret_cast<::FILE *>(SCANF_STDIN), format, args);
  36   // This is done to avoid including stdio.h in the internals. On most systems
  37   // EOF is -1, so this will be transformed into just "return ret_val".
  38   return (ret_val == -1) ? EOF : ret_val;
  39 }
  40
  41 } // namespace LIBC_NAMESPACE_DECL